If you want a lot of grain without too much contrast, the first step is to overexpose like mad. Add five or more stops *before* you consider reciprocity loss, which is fairly bad with Tri-X. Then, you want to give the minimum amount of development that you can, but do it with a "harsh" developer. I might try a dilute form of D-19 with a semi stand development. One Gal. of D-19 is good or 45 rolls of 120/135 or 180 sheets of 4x5. This means Kodak recommend a minimum of about 3 oz. stock D-19 per roll. I would quarter this amount to start: 3 oz. for four rolls, in as much water as it takes to fill the tank.
Rodinal or Acufine might be better choices, but I cannot say from experience; only from recommendation.