i do my lollipopping about two weeks before i switch to flower, then i do a light pruning when the buds have formed up good, maybe 30% of the total leaf cover. i pick the ones in particular that are blocking light and growing in toward the center of the plant. about a month after that, i might remove 10-20% again, as they grow back and block the same spots.
i used to never do it, was finally talked into trying it, and it seems to work to me. i'm getting noticeably more yield, and nicer looking buds. and that's my results only. try it, and if you don't like it, don't do it.