I can't give advice on the TP, as I don't own a 392. I would, however, recommend either a lighter valve spring or cutting the one you have down for better power potential. My 1322 with a 14.6" barrel hits 12 FPE using a light valve spring and a SSG with a flattop piston/valve (slightly hogged out for more volume) and a retained air setup through a stock transfer port. With a properly adjusted pump and a lighter valve spring, the 392 should have no problem hitting the numbers you are looking for. With a retained air tune, you could probably hit those number with fewer strokes between shots as well.