Since you are already using them I assume you already add "legs" to them - so you should be able to use any JFET tester that you find that works for you.
As for quality control - I have heard from pro pedal makers (at NAMM) that SMD is much better for quality control than through hole. Here is a good article that says SMDs are definitely better in terms of tolerance:
http://surfybear.weebly.com/test-rigs.htmlThis guy built a unit to test four JFETS at once from an arduino kit.