For that reason, you do the CG adjustments with the tank EMPTY for planes with the engine and tank in the front.

And, Audi, you're welcome. That was drilled into me by my instructor for practically every novice flight I did with him on the buddy box. So, I remember.. oh boy do I remember... But, it is in fact true. Moreso for trainers, but nevertheless, an ever present issue to deal with when changing trim.

CGr.