So having extracted 1% from my very first attempt at the Lazyman STB tek, I thought I could possibly expand on this with a short A/B at the start to see if even more can be extracted from my precious MHRB.

I want to do a test;

Take 50g MHRB powdered.
Add 750ml of Water/Vinegar (pH4 or close) to a pan.
Add MHRB and simmer for 1 hour 30 mins.
Allow to cool, strain bark and and transfer MHRB liquid to a jar, add clean water to make 750ml again.
Add Lye until pH13 is reached, mix and leave for 12 hours, stirring periodically.
Warm solution to 100-110f, add 50ml Naphtha, mix and settle 5 times.
Extract Naphtha and fan evaporate to 50%. Freeze precipitate. Make 4 pulls.

So instead of a cooking the bark over and over collecting the liquid like a regular A/B, just do it once and leave all the bark in.. ?

Feasable, but from experience of using powdered bark, that bits of park will mix with the solvent. I found it easier to boil/strain a few times and reduce that liquid to a certain volume.

Exactly, it's worth straining out the bark so that the solvent separates more easily in the base stage. Not all 'short cuts' will save you time.

That said, Cyb described a similar 'A2B' (acid to base) method that left the bark in so it's not like it absolutely won't work. There are relative advantages and disadvantages and it would be a useful exercise to think them through and write them out