Just picked up a Ripper 415. Installed the LUMIX spreedring scope (1.5x5/32). Had trouble getting it to work. If the triangle was on at 20 the rest would be off. Didn’t seem to matter what I did with speed setting. I have read the scope needs to be on at the centerline setting (which is 50 yards on some scopes?). Does anyone have any advice about getting this scope set properly?