Q1. can I reuse this developer again, and for how long/what capacity
To answer my own question - - YES you can. The 1:25 solution I made up a week ago and had pulled 1 x MGRC as "seasoning" plus 2 x slavich I have just re-used to pull another 1 x slavich and it appears to have worked exactly as it did last week. The developer was bottled and is presently a very pale yellow colour. Next time I'll just use it as "old brown".