Basically what I did was say without the remote needle the flow where it ran best was 80. So i richened the needle from there and set up the remote needle and in the middle of the throw I set the flow going through the remote needle to 80. At the pond that was now too lean, engine sagging out, I kept richening the remote needle till I was getting good runs. At that point the flow through the remote needle was around say 70.
Jack, with regard to the fuel flow chain, your meter flow number is going to be indicative of the point of maximum restriction.
The Barr/Violet needle is the choice of most high nitro racers. Why?...any cross sectional restriction is less than other 3rd channel assemblies.
Notice on the OS In Flight needle you're given 2 separate needles- that scenario points to 2 different tapers, dependent on engine size.
As some have mentioned, flow your system WITHOUT the 3rd channel in line, make sure there's NO needle restriction in the carburetor. Reinstall 3rd channel device, adjust the needle all the way out, and also the 3rd channel mechanism to full rich.
Take a flow reading....both readings should equate, if not, the restriction points to the 3rd channel apparatus.
Personally, I use both Barr/Violet and OS/Ferrette devices, but both are modified for greater fuel delivery in full rich status.
Regarding fuel blocks for the OS setup, there is none better than Don Ferrette's available in retail.
In finality, these engines and fuel delivery systems are NOT designed by the OEM 's to run on high nitro %'s.