I am building my own SVT-610FLH. On the ampeg website there is a angled view of the cab and it is see-through. It apears that there are levels between each level of speakers. Do you guys know if these levels are air tight, have holes, or even exist in the construction? Also, does ampeg insulate their cabs with polyfill or anything? ----thank's so much! O! one more thing, could someone tell me the angle of the slops that the bar and casters are attached too.