Just try cooling the image tone of the Bergger Neutral Tone with something like GP-1 gold toner afterwards. Or another tweak you could try is substituting benzotriazole for KBr as the restrainer in 130, but at 1/10th the gram wt quantity. Actually, I use an equivalent of GP-1 at about an eighth of the recommended dilution. Seems like every forumla wants to waste gold chloride, when it's entirely unnecessary. The paper will only hold so much. How long a VC paper needs to be developed depends not only on the temperature, but on how much the high contrast layer has been exposed in the first place, or a sufficient combination of both layers. There are no hard rules, and never will be. "Full development" all depends not only on the specific paper and development concentration, but the specific image as well. I develop anywhere from 1-1/2 minutes to 5 in 130, though 2 to 3 min would be the most common. Get that whole suite of variables pinned down and predictable, and then you'll begin to notice that significant temp variables DO themselves have an effect on final color. But all of this is in relation to the freshness of the glycin itself - one more variable that can be fine-tuned into the total outcome.