A Simple Specimen of Variable-Length Symbol Italian Cipher with Ambiguous Reading Frames

Many Italian figure ciphers employ variable-length symbols written continuously. This means one cannot tell from a given ciphertext whether "7333" should be parsed as "73 33" or "7 33 3." In Variable-Length Symbols in Italian Numerical Ciphers, I described various ciphers that have some schemes to prevent confusion, and also pointed out that there are some in which "no particular precaution against confusion is employed." For example, "525" can be read as "5(a) 25(a)" or "52(t) 5(a)." With such a cipher, even if one possesses the key, one can never know whether "525" should be parsed as "5 25" or "52 5", without knowledge of the vocabulary.
Such an ambiguity in the reading frame poses an additional difficulty in codebreaking. I suspect two of the three new Vatican Challenge ciphers use such a cipher.

Recently, I came across a specimen (Rome, 20 August 1604, unsigned) of an Italian ciphertext with continuously written figures with ambiguous reading frames (e.g., figures "3"(a), "6"(b), "9"(c) are also used in two-digit figures "33"(m), "36"(n), etc.). Unlike many other ciphers used at the time, this cipher is not homophonic, but a simple monoalphabetic cipher with a regular arrangement.
Hopefully, a specimen of such a simple cipher may give some hint of how to parse continuously written figure streams into separate figures.

99(-)98(-)30(l)3(a)33(m)6(b)3(a)54(s)9(c)27(i)3(a)12(d)29(o)48(r)15(e) 36(n)29(o)54(s)57(t)48(r)29(o) 48(r)27(i)57(t)29(o)48(r)36(n)3(a)57(t)29(o) 42(p)29(o)9(c)24(h)27(i) 21(g)27(i)29(o)48(r)36(n)27(i)
54(s)29(o)36(n)29(o) 12(d)27(i) 54(s)42(p)3(a)21(g)36(n)3(a) 48(r)3(a)9(c)29(o)36(n)57(t)29(o) 27(i)36(n) 54(s)15(e)36(n)3(a)57(t)29(o) 30(l)27(i) 33(m)29(o)30(l)57(t)27(i) 12(d)27(i)54(s)21(g)60(u)54(s)57(t)27(i)
9(c)24(h)15(e) 45(q)60(u)15(e)30(l)30(l)27(i) 33(m)27(i)36(n)27(i)54(s)57(t)48(r)27(i) 42(p)48(r)15(e)57(t)15(e)36(n)12(d)29(o)36(n)29(o) 48(r)27(i)9(c)15(e)v(60)15(e)48(r)15(e) 12(d)27(i) 45(q)60(u)3(a) 54(s)15(e)36(n)
12(d)29(o)54(s)27(i) v(60)27(i)54(s)57(t)3(a) 57(t)3(a)36(n)57(t)3(a) 3(a)30(l)27(i)15(e)36(n)3(a)69(z)27(i)29(o)36(n)15(e) 12(d)3(a)30(l) 54(s)15(e)48(r)v(60)27(i)69(z)27(i)29(o) 12(d)27(i) Midas 9(c)29(o)36(n) 57(t)
3(a)36(n)57(t)27(i) 54(s)15(e)21(g)36(n)27(i) 3(a)42(p)42(p)3(a)48(r)15(e)36(n)57(t)27(i) 15(e)57(t) 42(p)3(a)48(r)57(t)27(i)9(c)29(o)30(l)3(a)48(r)33(m)15(e)36(n)57(t)15(e) 9(c)24(h)15(e) 54(s)27(i) 9(c)29(o)36(n)42(p)
29(o)48(r)57(t)27(i) 45(q)60(u)27(i) 42(p)15(e)48(r)54(s)29(o)36(n)15(e) 9(c)24(h)15(e) 3(a)v(60)27(i)54(s)27(i)36(n)29(o) 15(e) 48(r)3(a)21(g)21(g)60(u)3(a)21(g)30(l)27(i)36(n)29(o) 9(c)29(o)54(s)57(t)27(i)
57(t)60(u)57(t)57(t)29(o) 45(q)60(u)3(a)36(n)57(t)29(o) 42(p)3(a)54(s)54(s)3(a) 27(i)36(n) 27(i)57(t)3(a)30(l)27(i)3(a) 54(s)42(p)15(e)57(t)57(t)3(a)36(n)57(t)15(e) 3(a)30(l)30(l)15(e) 9(c)29(o)54(s)15(e) 12(d)27(i) Midas
3(a)48(r)57(t)15(e) s(54)42(p)3(a)21(g)36(n)29(o) 30(l)15(e)54(s)9(c)3(a) 9(c)24(h)15(e) v(60)29(o)21(g)30(l)27(i)29(o)36(n)29(o) 27(i)36(n)18(f)15(e)48(r)27(i)48(r)15(e) 3(a)30(l)57(t)48(r)29(o) 42(p)15(e)48(r)29(o) 15(e)
6(b)15(e)36(n)15(e) 30(l)3(a) 36(n)15(e) 54(s)27(i)3(a) 3(a)60(u)27(i)54(s)3(a)57(t)3(a) 24(h)27(i)15(e)48(r)27(i) 30(l)3(a)30(l)57(t)48(r)29(o) 12(d)60(u)15(e) 6(b)3(a)48(r)9(c)24(h)15(e) 12(d)27(i) 18(f)27(i)36(n)3(a)30(l)15(e) 42(p)48(r)
15(e)54(s)15(e)48(r)29(o) 30(l)3(a) 18(f)48(r)15(e)21(g)3(a)57(t)3(a) 12(d)15(e)30(l)30(l)27(i) 21(g)60(u)3(a)48(r)12(d)27(i)3(a)36(n)27(i) 12(d)15(e)30(l) 9(c)29(o)33(m)33(m)15(e)48(r)69(z)27(i)29(o) 9(c)29(o)36(n) 57(t)60(u)57(t)
57(t)27(i) 30(l)27(i) 24(h)60(u)29(o)33(m)27(i)36(n)27(i) 9(c)24(h)15(e) v(60)27(i)15(e)48(r)3(a)36(n)29(o) 54(s)29(o)42(p)48(r)3(a) 45(q)60(u)3(a)30(l)27(i) 54(s)29(o)36(n)29(o) 54(s)57(t)3(a)57(t)27(i)
33(m)3(a)36(n)12(d)3(a)57(t)27(i) 30(l)27(i)21(g)3(a)57(t)27(i) 3(a) 33(m)27(i)30(l)3(a)36(n)29(o) 42(p)15(e)48(r) 24(h)3(a)v(60)15(e)48(r)15(e) 15(e)54(s)54(s)3(a) 48(r)27(i)9(c)29(o)36(n)29(o)54(s)9(c)27(i)60(u)57(t)29(o)
60(u)36(n) v(60)3(a)54(s)9(c)15(e)30(l)30(l)29(o) 9(c)3(a)48(r)27(i)9(c)29(o) 12(d)27(i) 29(o)30(l)27(i)29(o) 9(c)24(h)15(e) v(60)15(e)36(n)27(i)60(u)3(a) 3(a)30(l) 12(d)15(e)57(t)57(t)29(o) 30(l)60(u)29(o)21(g)29(o)
27(i)30(l) 45(q)60(u)3(a)30(l)15(e) 60(u)3(a)54(s)9(c)15(e)30(l)30(l)29(o) 36(n)29(o)36(n) 24(h)3(a)v(60)15(e)v(60)3(a) 30(l)3(a) 30(l)27(i)9(c)15(e)36(n)69(z)3(a) 9(c)29(o)54(s)27(i) 18(f)60(u) 42(p)48(r)15(e)54(s)29(o) 15(e)57(t)
42(p)15(e)48(r) 12(d)27(i)54(s)42(p)15(e)57(t)57(t)29(o) 18(f)15(e)9(c)15(e)48(r)29(o) 3(a)48(r)33(m)3(a)48(r)15(e) 30(l)15(e)54(s)60(u)12(d)15(e)57(t)57(t)15(e) 12(d)60(u)15(e)6(b)3(a)48(r)9(c)24(h)15(e) 3(a) 42(p)27(i)
21(g)30(l)27(i)3(a)48(r)30(l)3(a) 9(c)29(o)54(s)3(a) 9(c)24(h)15(e) 12(d)3(a) 15(e)54(s)57(t)48(r)15(e)33(m)39[e?] 12(d)29(o)30(l)29(o)48(r)15(e) 3(a)30(l)30(l)3(a) 57(t)15(e)48(r)48(r)3(a) 57(t)48(r)3(a)57(t)57(t)3(a)36(n)
12(d)29(o)54(s)27(i) 12(d)15(e) 57(t)60(u)48(r)6(b)3(a)57(t)3(a) 27(j)60(u)48(r)27(i)54(s)12(d)27(i)69(z)69(z)27(i)29(o)36(n)15(e) 15(e)57(t) 12(d)15(e) 30(l)3(a) 42(p)48(r)29(o)v(60)27(i)54(s)27(i)29(o)36(n)
15(e) 15(e)30(l)30(l)3(a) 30(l)29(o)54(s)3(a)42(p)48(r)3(a)

The plaintext is:
--lambasciadore nostro ritornato pochi giorni
sono di spagna raconto in senato li molti disgusti
che quelli ministri pretendono ricevere di qua sen
dosi vista tanta alienazione dal servizio di Midas con t
anti segni apparenti et particolarmente che si conp
orti qui persone che avisino e ragguaglino costi
tutto quanto passa in italia spettante alle cose di Midas
arte spagno lesca che vogliono inferire altro pero e
bene la ne sia auisata hieri laltro due barche di finale pr
esero la fregata delli guardiani del commerzio con tut
ti li huomini che vierano sopra quali sono stati
mandati ligati a milano per havere essa riconosciuto
un vascello carico di olio che veniua al detto luogo
il quale uascello non haveva la licenza cosi fu preso et
per dispetto fecero armare lesudette duebarche a pi
gliarla cosa che da estrem[e?] dolore alla terra trattan
dosi de turbata jurisdizzione et de la provision
e ella losapra