GX35/GX50 Fuel Tank Relocation

Here's my tank with a diaphragm carburetor on the engine.

so I testing it from a remote tank that was maybe 4ft below the engine and it works a treat

In fact, the return only seems to operate when you use the plunger (I think this is what you said/meant anyway)

Based on the above, I may just run the return into a small catch tank that is already mounted next to the engine if the only time I’m going to see fuel is when I use the plunger to draw it through. Do you see any issue with this?
The return generally doesn't return alot of fuel, it is still returning fuel, just not alot