The grayling is OK but no where near the jig that the Bitz is. I have both of them and never use the Grayling any more. I went cheap first like you are thinking about and still ended up with a Bitz.

The Grayling is very similar in its design but the plastic is no where near as precise as the ground aluminum of the Bitz. Usually you will have to sand down the clamp to get it even enough to get good contact between the vane and shaft with the Grayling.