I am interested in compounding a general purpose film developer for medium and 4x5 formats aiming for maximum shelf life and concentration. There is plenty of info on Rodinal-type developers but wonder just how concentrated you could make a PQ or MQ developer? Basically, I guess, how much of the ingredients, especially sulfite and carbonate you could get into a liter. I am currently using Sprint standard developer and like the 1:9 dilution which makes a gallon cubitainer go a long way, but it costs $68 plus $18 for shipping!! Thanks.