Hehe, we'll discount this preamble for the moment:
I just wrote up a mini A/B description
in this post, but try not to tell anyone
as it's meant to be an initiative test
and address a few of your questions…
What temp is a warm pull and why use warm pulls ?
Warm and not hot because it's advantageous to keep things below the melting point of DMT when going for a saturated NPS solution. Using warm solvent is based on the same principle as freeze precipitation - the temperature-solubility gradient. It allows more DMT to dissolve in a given volume of solvent than it would at room temperature, just as less DMT dissolves in freezing cold naphtha.
IMPORTANT: only ever use a hot water bath to warm your base soup and solvent, and extinguish all naked flames as well as moving out of range of incandescent material before measuring out any naphtha. Avoid all likely causes of electrical sparking when handling warm naphtha. (Hopefully all common sense, but definitely worth reiterating - vapour explosions and fireballs may cause damage to health and property.)
Should I add the base and salt directly to the dmt vinegar or prepare a water based solution and mix the two ?
Better to dissolve the base (you can use sodium carbonate, especially if there's no excess of acidity, which would be liable to foam a bit) and then drip that solution in and marvel as it turns milky from the separation of freebase DMT.
How do I know the aproximate quantities to use ?
If you know the amount, in grams, of DMT you'll be purifying, molecular weight calculations can be used to determine the precise amount of acetic acid needed to convert it all into salt form, and extend that to the amount of vinegar required by scaling to the percentage strength of the vinegar you're using.
A similar set of calculations can be carried out for the base you'll be adding.
We even have some solubility estimates for DMT freebase in naphtha, although a series of small pulls will usually work out better than one big one, so you can estimate the efficacy and level of completion by freezing each pull separately without having to calculate an exact amount of naphtha.
There's also a degree of variability between diferent batches and brands of naphtha, since it's a mixture with a range of possible compositions. This in turn affects the exact amount of DMT (or whatever solute) that any given batch of naphtha will dissolve, so giving a precise frgure here isn't altogether feasible.
And if I use a very small volume of solvent, the proportion that's really hard to pipette out without getting the base too will be quite big ?
Finding a container with a long, thin neck will help with pipetting, and there's also the inverted funnel trick. Either of these will serve to concentrate the naphtha into a narrow surface area, increasing its depth and minimising losses in the smaller amount of hard-to-recover naphtha remnant.
This is also where doing multiple pulls helps - each pull dilutes the remnant amount so that, by the time a fourth or fifth pull gets done, losses will become insignificant through repeated dilution: the remnant from a preceding pull gets taken up by the one that follows.
Final footnote: if the DMT has cleared up nicely through acidification, after the requisite amount of base has been added you may want to try putting it in the fridge to solidify into more or less of a single mass for simple physical removal. Crystals can then be obtained by recrystallisation from the minimum amount of warm naphtha or heptane. Slower cooling makes bigger crystals.
Hope this all helps!