If it's a problem you'll notice it after you take off and burn off some fuel.
I assume with a 10 oz tank you are running a .60 size engine. 10 ounces of fuel in a 6-8 pound airplane is not really a lot of weight, so the CG of the plane won't be moving much. I was criticised earlier for saying that CG would be critical. More specifically, a flying wing has a small CG range compared to a conventional plane with a long fuselage and a large horizontal stab. My Sig Wonder was <nearly> a flying wing, and it had to be balanced juuust right. I could notice the balance/trim change as the 4-0z tank, well in front of the CG, burned off. You're doing the right thing putting the tank at the CG.

I assume you will use a pusher installation. One thing sometimes not realized with pushers is that you should still have the connections to the tank in front so the clunk is in the rear. You want the clunk deep in the fuel while you are climbing, not sticking forward into an air bubble.