Am I an idiot for wanting to boost a high compression 318?

Easily?
When you add boost, you need to totally revamp your fuel system, decide if you're going with a draw through or blow through system; if you go blow through you'll need a custom carb ($$) and if you go draw through it turns into a plumbing/linkage nightmare.
It can all be done, but far from "Easily".

So with getting a Holley Sniper I was also going to get an EFI fuel tank with 340 LPH from efi system pros (see link below). Do you think that will be enough for the super charger? Efi system pro recommended Holley 550-540 Sniper XFlow EFI System Silver for this application

EFI Fuel Tank System, 1970-76 Dart / Duster / Valiant / Scamp