ORIGINAL: BILKO1
Correct me if i'm wrong but i thought moving the msn was a big no no. If you do move it you have to remove the hsn and housing then with the msn flush move it till one of the 4 holes lines up that you will see through the hsn housing hole.
Moving the MSN is no big deal when your seting it up to start. It doesnt matter where the holes are as there is a space around the MSN to allow all 4 holes to provide fuel to the throat.
Once you've set the MSN it is ADVISABLE not to touch it again as it WILL affect the idle, LSN and HSN settings. What I do is set it up as I said then silicone it in place. This not only holds it in place but seals it up properly as when these mills where new they had a problem with the o rings perishing, just something I never got out of the habit of doing.
Now if your engine suffers a mid range dip in accel this is when a tweak of the MSN can help. BUT you will need to fatten up the LSN and HSN a tadge and by doing this it may affect the idle. The reason they say NEVER touch the MSN is because folk dont adjust the other needles to compensate and end up leaning out their engines inadvertantly.
Hope that squares you away Bilko.