I am wondering if any of you have any clever scheme's for getting the most out of an A/B extraction.

I am doing veg oil extractions and I usually end up with about 10-15 good doses oral doses from 100g of plant matter (confusa or mimosa). I can't really measure my yields because I end up with acetate and have not been able to convert to a measurable freebase powder (it usually becomes goo after basing and extracting with acetone or naptha).

So I estimate my yields at probably around 1%, which is not bad but it would be great to reach a consistent 1.5 or even 2%. (I'm a bit jealous of others getting 2% from ATB and STB methods). ATB and STB don't work so well with veg oil because the plant matter absorbs so much of the oil, and increases the volume of the mixture considerably.

I think the limiting factor must be the acid phase. I usually use a decanting method rather than the standard 3x boils, since in theory you shouldn't need to boil powdered material. Boiling seems to create a very cloudy solution which takes much longer to settle. I usually boil the mix at the end of the decanting just to make sure i get everything out, but by then the water that comes out is murky but lacking the dark color of the initial decanting. Anyway, so boiling up acid water and then mixing that with the powdered plant matter and sucking off the supernatant with a baster once it has settled. I am using vinegar as the acid, usually starting with 250ml and then adding a dash with each subsequent wash.

In my next extraction i will try doing the standard 3x boil with some decanting after, using vinegar and also citric acid to maintain the acidity during the boil.

Any other ideas? Would the freeze-thaw idea but a good thing to try for improving the efficiency?

There is no hard data that freeze-thaws increase yield but many people do it anyway and think it helps. The idea makes sense as it helps lyse the cells by freezing the water around it making it expand and break the cellular structures down, if you want to increase yeild then it cant hurt.
Try freeze thawing in acidic water then if youre not bothered about boiling and in no rush then after its thawed just let it sit in the acidic water for a week. You could add ethanol for extra pulling power.
Remove plant material then reduce on a stove to 300ml basify then use veg oil.
Also to consider is the bark, maybe you are maxxing it out already but its certainly worth a try.
If you are concerned about ethics/ environmental impact you may want to look into if your vege oil is palm oil and if its from a certified sustainable source.

do you think doing a B-A-B might make any difference ? So mixing with sodium carb, making it pasty, letting it sit and then acidifying with citric acid, decant, base, pull etc..?

My thought here is that people seem to get higher yields doing ATB and STB where the plant matter remains in the basic mix. So if basing the plant matter helps to get the good stuff out more so than basing an extracted tea, then this might make it more efficient.

Maybe, its impossible to say without experimental data. Its been seen that many would get good results from a series of A/B until you have a concentrated shot of alkaloids that can be pulled in a minimum amount of solvent.
Cybs ATB is certainly a good tek to start with. You could of course add an intial basing of the soup to make if you wanted.
Not using heat does seem to produce a cleaner solution to basify, which means less crap is going to get caught in the solvent.