i think it really depends on your setup, flat reed? or pyramid? what thickness and quality of reed are you using. Also if you pull it up too much the reeds may never close or even snap due to too much travel.
i would think more travel = better throttle responce and maybe lowend, but more likey not to close enough at higher rpms
i think yes on a flat reed setup like a tomos the angle of metal or amount of travel the reeds have will make a difference, as to whats better, anything you do to make a part of your power band better will adversly effect another part for the most part.
go try some shit till u break it, thats what i'd do.
i've heard alot of talk about this stuff reguarding advanced scooter tuning but haven't really tried messing with it much myself, the bike is pretty good right now, if anything i may want to make heavier reeds so they snap back sooner so my top end gets a little boost, without messing with the amount they open when fully extended.
well at least thats the theory haven't tried any of this so don't take it as solid info.