Microdol-X will deliver better grain, but the price is a bit steep: some effective speed loss, some sharpness loss, "flat" negs requiring harder VC filtering to get punchy prints... And when I used it, it seemed to somehow attract far more crud than usual to the negatives (undissolved chemical grains, hairs, dust, other sludge) even though I followed all my usual procedures. One of the ways MicX improves grain is by dissolving the individual grains, which unfortuantely also starts to compromise sharpness...(posted 9195 days ago)Overall, I have always been very happy with D-76 1:1. I'm now in the process of trying out XTOL, since so many people are raving about it, but I haven't tried it with Tri-X yet. (Actually, I'm trying it with the 100-speed films that I shoot in my Minox. In Minoxery, finding a developer that reduces grain without compromising other positive attributes is akin to the search for the holy grail!)
BTW, I NEVER would have guessed DK-50! We (my parents have been pros for over 50 years) use it for sheet film (Ektapan, PXP, TX), but I always considered it a harsh, fast-working developer that only delivered average grain - fine for large format, but not a good choice for smaller formats.
In terms of RC paper, I've been using Luminos Flexicon almost exclusively for several years. I think it's wonderful stuff, and very reasonably priced.