And I haven't tried it with either APX or Acros. I have three unopened, always frozen boxes of 4x5 APX 100 in my freezer (well, always frozen save one week long power outage up in TN and the trip to bring it down here - and even then I put it in a cooler with ice packs.) Expiration on it is 1997 IIRC so I'm not sure how good it is (and no folks, not for sale - unless you want to pay outrageously! ) so I may give it a shot.

It does make temperature a non-issue. I learned of it in high school from a fellow teenage ham who was the yearbook photographer at his school while I was at mine. I shot lots of Tri-X at 1600 in it. Still have the negatives (most have survived, last I looked) and a shoe box of prints. Occasionally I'd shoot Plus-X at 500. Diafine box said 400 but I gave it 1/3 stop less after trying it. I still use it with 35mm and 120 Tri-X, but it's odd - modern Tri-X has some t-grain characteristics. I noticed when TMY came out that it seemed much slower in tungsten light than Tri-X. Kodak's sensitivity curves do NOT bear this out, but it was my experience, and still is - got some underexposed 4x5 negs to show for forgetting that. Now Tri-X seems to do the same thing. In tungsten 1000 looks decent. In daylight that will look dense.

I have been meaning to try it with 4x5, though. I have a Jobo and 2509n reels and tanks, so temperature control is easy. Set the dial to my pre-calibrated 75F I use for all BW and forget it. I have trays, but also have my old deep tanks and hangers, which might be an easier way than trays to do 4x5 in Diafine. I've been meaning to give it a try.