Need to drop the fuel tank but it is currently 80% full

[JayHow]

I have been dealing with EVAP issues, exhaust leaks due to broken bolts at the manifold, and other issues I'm trying to address on my 2005 GMC Yukon SLT (4x4, VIN T, Non-Flex) to get it to pass emissions.

I replaced the charcoal canister and vent valve and can now fill my tank just fine. However, I noticed a leak at the fuel tank while replacing the canister and vent valve. The tank looks wet on the rear passenger side down to the bottom of the tank and I have noticed the smell a few times walking around the vehicle. It seems pretty minimal, I haven't seen any gas dripping on the ground at all.

I need to drop my tank and see what is causing it, but of course I just recently filled up the tank (at about 80% full right now). I am not sure how to go about safely handling this... Any suggestions? I live in an apartment and I don't have anything/anywhere to store the gas in if I were to pump or drain it from the filler hose. Can I still drop the tank that full and it will just be heavier, or is that dangerous/stupid? Will a shop drain the tank for me? If so, will it cost me an arm and a leg?

I have 0 experience with this as you can probably tell.

 

[Scottydoggs]

id run the tank down to E. gas is like 8 lbs a gallon. so easy 200 lbs in a full tank.

the lock ring for the fuel pump on top of the tank likes to rust away, then leak from the top of the fuel pump.