I'm getting ready to use the procedure with NH4NO3 + H2SO4 -> HNO3 + w/e the ammonium salt is. i've heard some say a magnetic stirrer on low speed with a burrette dripping glycerine in works great cause you get such even mixing, but i've also heard that the friction and general rapid movement of the stir bar COULD set off the unstable acidic NG.
i'd really like to do it this way if its ok. opinions?

As I understand it many people have done it with magnetic stirring without incident. Accidents can always happen though.

Teflon coated stirbar on glass... shouldn't be much friction too... so... personally I think you would be fine... but YMMV.

I've done it many times, never had any thing happen yet

I use a plastic spoon.

sweet i'l probably do that on low speed today then.

other thing is given the reaction and that it does make an ammonium salt... is that filterable? i have a buchner funnel I was thinking of doing so with. i'd imagine having that solid in the vessel could add some friction, but will the acids just destroy the filter paper so quick in the process that it wouldn't matter?

No, you gotta distill to get the nitric out.
I believe the reaction goes H2SO4 + NH4NO3 --> HNO3 + NH4HSO4 The ammonium bisulfate turns the nitrating mix in to a thick goo. NG is easiest with HNO3 instead of the nitrate salt route.

i don't have that great of means to distill the nitric. will i be ok using it with the sulfate salt still in there? I can notice the viscosity a bit, but it's not what i'd call a "thick goo", and the stir mechanism has no problem working through it at low speed (almost 0 vortex)

I've never used NH4NO3 for NG, always done it with KNO3. This (http://s6.photobucket.com/albums/y240/nuclearrabbit/?action=view&current=NGputty.flv) is what it looks like with all the glycerine in using KNO3.
It still works you just have to wash the NG a little more.

i always use the NH4NO3 method
works fine all the time

edit
rabbit you should try using ammonium nitrate, its so much better...its more liquidy and not as thick when you synth it..plus it dissolves very well into sulfuric acid

Forget NG. Get some pure glycol and make EGDN instead. Its cheaper to make, less sensitive, easier to stir and neutralize, more chemically stable and most importantly more powerful.

or just make etn