Can i make relative delays in timequest (9.1)

As mentioned, there is a slow and fast sub-model within a corner, which is good, but personally I think it is too high. Specifically the on-die variation would be a lot higher between two pins on opposite side of the die than two pins next to each other, but only having two models, locality and other things can't be taken into account. (I think it errs on being pessimistic, which is good).

As for the fitter, it can but not in a good way. The placer tries to put all things closer together and wouldn't spread things out. The router is where delays can be added, but it's a pretty coarse tool. My suggestion would be to hand-place the registers into two LABs and see what the router can do from there. If you see a lot of variation, put it into its own hierarchy and make a partition out of it. Do a seed sweep, and lock down the best results with post-fit placement and routing.