argv0, I did see the site for js4mirc that I thought might have been interesting, but the documentation quickly shattered my hopes (plus it seems to only take strings which means I'd run into aforementioned issues again).
I'd prefer to stay within the mIRC language, but I might have to check out python4mirc at least.
I'll try shaving away some more milliseconds in the mean time as well.. and try it on a more modern machine - I might be fussing over a moot issue

If I get it to a reasonably releasable state, I'll be sure to post it here - there's bound to be parts that can be sped up in ways I'm not thinking of.