Emacs chess with custom engines

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Hi all
I have recently started to use Emacs (+EmacsWin32) and have enjoyed being able to play chess with it!
I am also trying to configure & use it as a programming editor.
It has default engines crafty & gnuchess (+ phalanx scid & ai which I haven't yet tried).
I have tried briefly to write my own .el module to use Numpty04 chess engine but haven't succeeded. I think it might be possible to add more engines to Emacs but maybe Numpty isn't compatible (I may try using Rybka2.2) and my attempt to add it as an engine possibly wasn't sound enough!

Does anyone have any experience of adding other engines or chess playing & programming in Emacs?

I look forward to replies, best wishes