However, if at all possible, could you plz try to find out why using many hoppers in conjunction with trapped double chests seems to lag my Xbox 360 minecraft right down to slower than a crawl, as I'm completely stumped.
Lots of hoppers cause lag. There is no way around it. They are always looking for stuff to pick up on top and take up bandwidth by doing so. You can reduce the lag slightly by putting droppers on top of the hoppers that do not need to pick up stuff from the top. Add to that the fact that chunks do not unload on old gen and you can max out your processor in no time. Large sorting systems are a no-no on 360 unless you want to lag the crap out of your game. The hardware just isn't powerful enough to perform all the calculations at 20 ticks per second.