Not sure whether this will get a response, but I too have been wondering about this idea of a reverse infusion mash. I’ve recently started building one gallon batches to expedite my learning curve (i.e. trial and error) so have some leeway to quickly experiment. This is all theoretical at this point, but briefly my thought is to take half my well shaken bag of milled grain and mash at 160F for 45 minutes (subjective) and mash out at 170F. As you all know, this single alpha rest produces a longer starch molecule, less fermentable wort. Setting aside to cool, I’d then mash the other half of my grain at 140F for 60 minutes as a single beta rest. So getting to the point and adjusting for volumes, my thought is to add the cooled alpha-rest wort, to the low temperature mash so beta amylase has the entire focus on the unaltered starches (new) plus the cooled alpha-rest wort. I realize there are several variables to deal with here like diastatic power of the low temperature mash, mash viscosity, mash duration and perhaps sparge efficiency. But if the goal is a highly fermentable wort then this may be a way to do it. I will soon know.