I once did similar, "pushing" Tri-X to EI 1,000, only to find it was FP-4 in the camera, not Tri-X. I souped the heck out of it in my standard, D23. The negs printed fine, but grain was pretty obvious.
In ye oldene dayz, TRI-X souped in straight D-76 often did well at an EI of 650, developed for the normal time (was that 8 minutes, 68F?, I forget). So a push to EI 1,600 should be doable if, as abpve states, you can keep contrast increases, some how, at a minimum. Perhaps 8 minutes normal, followed by water bath, with additional increments and water baths???