Hello,
I have purchased the brand new Magnum XLS 52 (http://www3.towerhobbies.com/cgi-bin/WTI0001P?I=LXHSL3&P=8) and will convert it to C/L by using the venturi and NVA instead of the R/C style carburator.
I do have the C/L venturi with OS Max 20-40 NVA from my old Magnum Pro 45 ( please see the attachment) and would like to use it in Magnum XLS 52.

The C/L venturi with OS Max 20-40 NVA from my old Magnum Pro 45 fits the Magnum XLS 52 crankcase carburetor hole reasonably well but needs to be secured in place.

I have two options here:

1. drill a 0.118" hole in the venturi shaft and use two existing holes in the Magnum XLS 52 crankcase to secure the venturi with a single screw going THOUGH the venturi flow below the OS Max 20-40 NVA.

2. Drill TWO holes in the venturi shaft, tap them and use two short screws to secure the venturi shaft. This option DOES NOT DISTURB THE FLOW BELOW THE OS Max 20-40 NVA INSIDE VENTURI.

Which one of these options is better from the venturi efficiency point of view?

Thanks,
M