Adapters vs. Intended Cell size - tell me

[muzikbiz22]

I've just purchased a UK C4 ELED light and was looking into using rechargeable AAs as described in this thread. My only remaining question is if using AAs with spacers could have an undesireable effect on the bouyancy of the lamp. Will it be too positively bouyant with all that new air space in the housing (to the point being annoying to handle) or will it be negligible?

I have the UK C4 eLED. When used with C's, it is negative buoyant. When used with AA's & spacers, it is EXTREMELY positive buoyant.