Hi Lee, I don't have the Long Lens Head, but I do have the GP head for almost a year now. I can say that it (the GP) is everything indicated and then some. Superb design and machining, great finish, and the GP can easily hold 25 pounds, although my heaviest is probably 5# (K20, FA31 and a Nodal Ninja is the greatest weight and mass I have had on it).
I would suggest calling Arcatech. I had a question prior to purchase and they (Scott the President, Designer, etc.) was extremely helpful and very knowledgeable. Have you watched the video on it. On the GP I found it to be very helpful.
Again on the workmanship and design I found the unit to be extremely well engineered and machined. The design on mine is simple, elegant and very easy to use. It was certainly designed for the user.
Hope that helps...