If it came to that, the RM2 has to be the easiest atty to bore out the air ever. It's brass and very easy to work with. You can even do it by hand with a bead reamer or any conical file. Some have even just used a drill bit by hand.
Buuuuut... once it's done, it's done. It prolly would make
sense to live with it as is for a little while - experiment with builds and dt's if you like. Also, Spydro's suggestion of slip streaming is a good one.
With a PTank, you were MTL inhaling, so it's not like you're used to something like a vector or derringer (which may be in your future, maybe not).