I havent tried the thumbscrew but I havent read anything good about it either. What I did was get a d-shaped end from motionpro:
http://www.motionpro.com/motorcycle/tools/90_degree_1-4_hex_driver/ It has a d-shape on one side and a quarter inch allen hex on the other side so I just used(I think) an extra quarter inch quarter inch socket(yes I meant to say that twice) that I had laying around. The d-shaped piece also has a ball bearing in it so it wont slip out of your socket. Now I have my tool that cost less than $7 and took no time to make. And it works great.
