Ive built 2 so far and in the process to making another two. The only have one suggestion..
For packing in and out of the blind, the 90 degree pvc attached to the bilge pump can be cumbersome.So instead, I just put a light coat of the 552 marine sealant on the nipple (or outgoing pump part) to create a tighter seal, and then drilled a small hole through to put a pin in it. Holds the 90 tight in there, easy to take apart and never had an issue.
Overall, ingenious idea and works great!