Oh crap, RESERVE isn't in the manual at all

So, it's pretty easy, just do like

RESERVE ts tl tsh kp

and it should work.

Ness: yeah, true, but I grab anything which is a diacritic, spacing modifier letter, combining mark... anything in classes LM, SK, MC, MN, and the ASCII superscripts and anything between decimal ranges 8304 and 8348, and between 860 and 866 (the tie-bars).

I need to be more explicit about this. And probably make a better manual, like a real web-page even.