I just read this entire thread. Very interesting discussion from years ago. The eternal battle between 1/18 and 1/16 tanks.
I've taken a sort of compromise position. Larger vehicles I stick with 1/18. But artillery and small tanks, like the panzer I, FT, tankettes etc I will dabble in 1/16. Even though they are too big, they look ok because even in 1/16 they are still quite small...and I suspect it would be near impossible to get 1/18 figures to fit into 1/18 tankettes. It gets tricky as to where to cut off doing 1/16 and switch to 1/18 though. Haven't figured that part out yet.

Takom has made some really nice kits of small tanks/tankettes and there will probably be more.
Artillery is tricky because the crew look noticeably undersized beside it (wheel size, breach height are dead give aways). So I use the tallest most robust 1/18 figures I can...helps a bit. After that I just put up with it....
Still haven't been able to mix 1/18 medium and heavy tanks with 1/16 though.......that may be a bridge too far for me, always.
i never met an airplane i didn't like...