Hello Orion,
I don't recommend making your own conduit friction saver. You won't be able to find the extra flexible liquid tight flex steel conduit at a local supplier or at the big box suppliers (Home Dept, Lowes etc.) The savers that New Tribe sells have a smaller minimum bend radius. You can order the good stuff from an electrical supplier but the minimum order is typically 100 ft. The price of the New Tribe savers is very good, barely marked up from materials and labor cost, and they are well made.

The good thing about the triple action double lockers is that as long as the gate is closed the biner is secure. I'd go with the autolocks unless you have a really good reason to use the screwgates. With the screwgate all it takes is one time to forget to manually lock the gate and you are in trouble.

Any gate has the potential to be opened by the rope during climbing. You need to keep on eye on your biner whether it's an auto or manual locker.
-moss

I actually prefer screw gates over single twist autolockers. It does require the presence of mine to remember to always lock the screwgate, but the autolocker will accidentally open WAY easier.

Of course, it's best to forget all that and just get some triple lockers!