I've found Blu Tak very hit and miss - often not up to the job of keeping the figure on the base and losing adhesiveness at crucial times (often when the paint is being applied!).
Similarly PVA also comes with its own peculiarities. Its usually better for keeping the model on the stick but use too little and the model comes off, too much and casualties result as you break a leg or spear while trying to pry them off. In addition, the PVA can often seep over the top of the figures base and harden around the feet if not wiped away sharpish.
However, I was in Poundland the other day and spotted some double sided adhesive tabs for (you guessed) £1. They're the ideal size for 10mm horses and lines of 6mm infantry / horses. Indeed, with room to spare they could easily accomodate a 15mm / 28mm figure. In addition, the tabs can be cut in half to accomdate smaller based figures (so I'll try some Napoleonic Prussians to see how they get on).
Use is simple. Peel a tab off, place on an extra wide 'lolly stick' (they're too wide for standard lolly sticks) then peel off the top cover and you have an excellent stable base for painting. Once the figure is done, they come away fairly easily and (though I've yet to try) i'm sure could be re-used.
As a result, all my Gallic cavalry as well as my Parthian horsey horde have been re-stuck (replacing Blu Tak) - and I still have over half the pack AND a roll of double sided tape left! This will not stop me popping down to Poundland today to buy another 2-3 packs!