Revisiting smaller chess engines

[orac81]

I was experimenting with a very simple C chess engine for 6502 computers (see previous post: viewtopic.php?t=86366), something in the line of pre bitboard, classic simple byte board array, trying to make a really small engine that plays (relatively) ok.

I was wondering what lessons or small tricks learned from the modern engines might be valuable for this, perhaps things we know with hindsight?

I will give a very simple example - applying a small random factor to the terminal evaluation might improve play by avoiding bad forced lines, if there is an option to get the same score by many routes.

Conversely, what things should we not bother with, in hindsight?

I liked Olithinks engine, just using material+mobility as a reductionist approach.

On another point, I was trying to build UMAX with Oscar64 C, but the obfuscation is to much for it! Is there a non obfuscated version of this program? Its small enough to build..