While acknowledging the usual provisos and the massive development chart et al. does anyone have a good starting point for Delta 400 in XTOL 1+1 using an exposure index of 1600 (Mamiya 7II negatives)? I'd have thought about 20 minutes @ 20C / 68F but on second thoughts this seems slightly long.

I'm using stainless steel tanks and reels (hand agitation).