Hello @robzeke, thanks for your questions; here are the answers:
re slotted tubing:
Our motors are made for industry standard Rolease tubing, but the drive adapters can be modified to fit other types. Slotted tubing (internal splines) are good because they lock the motor drive. You can also use tubing or pipe with a smooth interior wall, but we suggest you use a locking screw to prevent slippage.
We have written a series of articles with a lot of detail that can be seen on the main menu at Rollertrol.com (see 'How To' and 'Projects')
Projection material can be heavy, so you may want to use our HD motors that have 24 lb lift capacity. One of the above articles explains how to measure the weight of your shade. You can use any kind of tension bar, as long as the fabric + tension bar weight doesn't exceed the lift capacity. We also have the Maxi, which can lift 45 lbs using a 2.5" tube.
We only supply motors, but you could do a search for screen material and tubing. The metal supermarket is one place to check for tubing. We also use 1.25" EMT steel conduit from any home hardware supply.
Regards, Adrian
Senior Tech
RollerTrol Automation Systems