Toss out characters that you don't need

[ProofOfKeags]

At a very bare minimum you will want 36 characters in your alphabet, for lower case and numeric stuff. Beyond that you will want spaces and common punctuation:

.,?:;"' <-- 7 characters

after that you probably want all of the shift symbols which is another 14.

Space 1

and then []{}/\ <- another 6

This comes to a total of 64 characters in the alphabet which can be squeezed into 6 bits. If every character takes 3/4 byte, you can fit 4/3 characters in the same number of bytes. This stretches the number of characters from 75 to 100.

This notably excludes capital letters and <>

[ProofOfKeags]

The previous message rendered with only that character set:

at a very bare minimum you will want 36 characters in your alphabet, for lower case and numeric stuff. beyond that you will want spaces and common punctuation:

.,?:;"' -- 7 characters

after that you probably want all of the shift symbols which is another 14.

space 1

and then []{}/\ -- another 6

this comes to a total of 64 characters in the alphabet which can be squeezed into 6 bits. if every character takes 3/4 byte, you can fit 4/3 characters in the same number of bytes. this stretches the number of characters from 75 to 100.

this notably excludes capital letters and gt lt