Fuel tank sender position problem

[jasongray5]

My tank arrirved today
Looking good and all that, however, slight mis-communication with the guy who made it and the sender hole is in the side, about 3/4 of the way up, instead of in the top, The sender I have came with a rubbery thingy, do we think it will be fuel tight, or shall I move it to the top, and weld a plate over where the existing hole is?

Cheers Guys Jas