While this doesn't directly answer Neal's question regarding Efke in D-76 I'll toss this into the pot...

Efke R100 (the 120 version) at EI 100. Late afternoon/early evening, mostly moderate lighting under clear skies. Some photos under open shade; others under open sky after sunset.

Neofin Blau, 30ml concentrate in 500ml distilled water (530ml total solution).

11:30 (eleven minutes, thirty seconds) @ 75F.

Three inversions every minute in stainless reel/tank system.

I was aiming for a higher contrast index to suit both the lighting and my dichro head.

Lacking a densitometer I'll just say the results are very good. Excellent tonality with very satisfactory contrast for the lighting conditions (described above). Shadow detail was good but could be a bit better - this film in this developer might be better at EI 50-80.

As expected from Neofin acutance was high with grain that was sharp and very tight. This developer might be best with TMX, Pan F+ and Efke 25.

Efke R100 might be best with D-76/ID-11, Microdol-X, Perceptol, etc., if one wishes to minimize grain.

BTW, my Efke R100 negs curled up tighter than an angry rattlesnake. Never saw such ferociously curled negatives. Fortunately I use a glass carrier in my Durst M605 so there's no problem. Tension from the curl actually helps with positioning the negs in this usually fussy carrier - if you've used this type of carrier you know what I mean.