Hmm -- may be off topic -- but whats up with wanting a tube? I can't quite get my wits around it.....and I know a lot of box feeders use it and use overflow wells and all that.
But---why not just tilting the box just above level & let gravity be the force. Heck, I do with my box mod while relaxing in bed and can even get the dreaded juice in mouth without pressing feed (only on very agressive long draws) --so--don't need the macho squank force.
To see what I'm talking about -- Just pick up any juice bottle --- especially one less than 1/2 full -- hold it horizontal and than look at how little one has to tip to see the juice be at the tip end. Now imagine a tube in there---uh, it won't provide any juice.
Must be a guy thing......or whatever floats your boat.