Delta 100 will work well with most any general purpose developer from D76 to XTOL to Rodinal. I find it loses too much speed in Pyro but that's only my personal preference. In the end it will look very similar to FP4 in terms of tonality, just with finer grain. What might be worth noting is in my tests I found DDX to give Delta virtually box speed without even resorting to alternate dilutions, agitation schemes etc. So if you want to shoot at box speed DDX is a good option. Grain is only slightly more prominent than in D76/ID11. But I found the recommended time of 12 minutes far too long. 8-9 minutes worked much better.