i have some kick ass rubber that we use to make gaskets for them. Shoot me your address and I will send you a piece. Just send the dimension of your plate so we get a large enough piece.
Eddie

viton???

Sometimes ,even when using the right gaskets ,people fail to pay enough attention to the individual sealing washers on each screw. .Some of the cheap senders are hard to seal no matter what.
My weak observation

When I build a fuel tank I make a billet weld in bung that has blind tap holes so fuel wont leak past bolts.
I use an o-ring with a groove machined into the bung.
Perhaps you could make a new plate that has an o-ring groove milled into it, the screws can be sealed with an o-ring by countersinking the holes .

Thanks Eddie ill get those dimensions for you on Monday. It's 2 plates but there fairly small. Thanks again

Pm sent eddie

I'll get it headed your way.
Eddie

Thx ill call u tomorrow so I can get u paid man.thx