I use Adorama store brand a lot and my normal dilution for dektol is 1:4. I used to use 1:2, 2 minutes and could never see much difference between 1:30 and 2:00. Now with 1:4 I usually go about 2:15, but I can't see much difference after 2:00. I use a method similar to single tray, except it's "single container".