Robert, Contrary to the above posts, you ARE on the right track for T-Max N+1. I have found that weaker dilutions of HC-110 (I use 1:63 from concentrate) give less fogging and more contrast that the standard, stronger dilutions. I could not get a usable N+2 from T-Max 100 until I swithced to this technique: I know it is counter- intuitive, but it does work, and work well. I print with a cold-light head, and my times (for you, a starting point only!) for T-Max 100 in HC-100 are:(posted 8283 days ago)N-1 8 minutes
N 11 min. 15 sec.
N+1 15 minutes
N+2 19 min. 30 sec
All for HC-110 diluted 1:63 from the concentrate, not a stock solution. This is for 4x5 inch sheet film developed by hand in trays with an agitation cycle of once through the stack every 60 seconds. If you shoot roll film, these may not be even close.
Note: HC-110 at 1:63 from the thick syrupy concentrate. If you live in Europe, especially France, you can get a different, less concentrated, watery concentrate which is already a 1:2 dilution of the concentrate I use. You will have to exprapolate to arrive at the proper dilutions. The longer times also help promote the formation of edge effects. Hope this helps. ;^D)