This is exactly why I use the nasal aspirator.  There is no drip back, the tip is very fine and can easily pull of 1/10" of solvent without disturbing the base layer.  It is extremely easy to handle and give the user a lot of control.  The one I have does not degrade at all with toulene, naphtha, or even xylene. I can't say the same for the poor turkey baster I used a few times.

I'd be awful careful of buying any watched chems in America.  You can rest assured if you arouse any suspicion you will get a knock on the door by some men with shiney black shoes.

If you keep the orders VERY small you should be ok.  Why would you want sulfuric acid when you can use phosphoric or HCL without arousing any suspicion?  Also the phosphoric acid I use is food grade, is dirt cheap, and does a wonderful job pulling out alkaloids really quick.

I learned my lesson about Siphoning.  A mouth full of lye juice and a mouth full of naphtha has completely convinced me that it just is not the way to go.  I don't do large extractions and keep my NP solvent pulls as small as possible for maxium saturation.  It takes more pulls, but keeps me from having to evaporate liters of hydrocarbons in the air (of my home nonetheless).