hi,
   i feel it depends  strongly on the circuit.Lets say if you are using poly resistor it is independent on process,so in this case for any thing more or less you will get same result,whereas some circuits like biasing,less resistor  value  may gives worst condition.If you are not in a position to decide worst corner,do both simulations(fast nmos,less res and fast nmos ,high res).
Thank you,
Rajasekhar.