wouldn't it be simple to get a longer tube from Jonah?
On the topic of making a 'depth charginator' the two are incompatible. the tubes are different diameters. You 'can' get a bigger tube from Vapor Age by getting the longer torpedo tank tube but imo that should have been the size tube it came with. I personally wont pay 50 bucks for sometihng then 4 more to make it what it should have been. It wont resolve the refilling issue either, the caps are very deep so you have to push the carto pretty far in to get juice in unless you use a needle and even then it's still a pain in the .....
On the topic of hte big daddy, I havn't seen those before. I'll check into em, if it's in the budget I'll order one to test. THe next tank I get will be going up against the current champ, the liquinator.