Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
For those who require higher tolerance and consistency with the two handed method consider this: Picture an artists easel with aluminium construction. The top is wall mounted with a piece of aluminium angle iron that grips the top of the screen. The bottom has the same piece to catch the bottom of the screen. Attached to this piece is a hydraulic shock from an auto supply store. This holds the screen firmly in place and accommodates different frame sizes. Downward motion applied to the screen releases it. A quick flip and you now coat the other side.These have been made. Some even have a swivel so you don't even have to release the screen to coat the other side.
I just have 2 pieces of 3/4" x 3/4" wood screwed into a table and use that to lean the screens up against the wall in the screen room... has worked fine for the 4+ years that I've been using it.never got used to doing a one-handed coat either.
http://www.vastex.com/Literature/C-100%20Flyer-NP.pdfVastex just came out with a new one like a week ago. I haven't seen it in person yet though. Looks pretty nice.