And here's a list of ways of representing numbers in short
code consisting of only lc letters and space:

The list has been updated.

-5 = log cos hex b
-4 = log sin hex affff
-3 = log cos ord c
-2 = log cos ord f
-1 = log sin ord t
0 = cos ord b
1 = length z
2 = log hex c
3 = length zzz
4 = log ord e
5 = log hex be
6 = oct ord uc e
7 = log hex aff
8 = oct ord l
9 = oct ord w
10 = hex a
11 = hex b
12 = hex c
13 = hex d
14 = hex e
15 = hex f
16 = hex hex a
17 = hex hex b
18 = hex hex c
19 = hex hex d
20 = hex hex e
21 = hex hex f
22 = hex hex hex a
23 = hex hex hex b
24 = hex hex hex c
25 = hex hex hex d
26 = oct oct hex fff
27 = oct hex hex hex f
28 = oct hex daa
29 = oct hex dff
30 = oct hex hex aa
31 = oct oct oct hex daaa
32 = oct hex fff
33 = hex hex hex f
34 = oct hex ffffffff
35 = hex hex hex hex b
36 = hex hex hex hex c
37 = oct oct hex daaa
38 = oct oct hex hex ee
39 = oct oct ord ord c
40 = oct ord hex dd
41 = oct hex caaa
42 = oct ord hex fff
43 = oct oct ord uc a
44 = oct ord hex ffff
45 = oct hex daaa
46 = oct hex hex ee
47 = oct ord ord c
48 = ord cos ord k
49 = ord ord o
50 = ord hex dd
51 = ord hex eaa
52 = ord hex fff
53 = oct ord uc a
54 = ord hex ffff
55 = ord ord uc n
56 = ord ord uc p
57 = ord ord c
58 = oct ord uc h
59 = oct ord uc i
60 = oct ord uc j
61 = oct ord uc k
62 = oct ord uc l
63 = oct ord uc mz
64 = oct ord d
65 = ord uc a
66 = ord uc b
67 = ord uc c
68 = ord uc d
69 = ord uc e
70 = ord uc f
71 = ord uc g
72 = ord uc h
73 = ord uc i
74 = ord uc j
75 = ord uc k
76 = ord uc l
77 = ord uc mz
78 = ord uc n
79 = ord uc o
80 = ord uc p
81 = ord uc qz
82 = ord uc r
83 = ord uc sz
84 = ord uc t
85 = ord uc u
86 = ord uc v
87 = ord uc w
88 = ord uc x
89 = ord uc yz
90 = ord uc z
91 = oct oct hex cd
92 = oct oct hex ce
93 = oct oct hex cf
94 = oct hex hex dff
95 = oct hex ord uc yz
96 = hex oct ord uc j
97 = ord a
98 = ord b
99 = ord c
100 = ord d
101 = ord e
102 = ord f
103 = ord g
104 = ord h
105 = ord i
106 = ord j
107 = ord k
108 = ord l
109 = ord mz
110 = ord n
111 = ord o
112 = ord p
113 = ord qz
114 = ord r
115 = ord sz
116 = ord t
117 = ord u
118 = ord v
119 = ord w
120 = ord x
121 = ord yz
122 = ord z
123 = oct hex ad
124 = oct hex ae
125 = oct hex af
126 = oct oct hex ord h
127 = oct oct hex ord i
128 = hex ord uc p

Update: oh, I forgot those ending with
ord plus a letter and
ord uc plus a letter, I'll check for those later.
-- update: done now

I, however, did check the ones with
length qr jzzz...zzzj
which could help as qr increases the number
with 9 for only 5 char's cost,
but it turns out that it's never the shortest.