48/170 is probably on the lean side. That's close to what we run at 1,000' above sea level.
I'd put a 50 or 52 pilot in and a 172 or 175 main and run it again. You're better off being a little rich than too lean.
Also, are the carbs synced?
Sorry, you're not qualified. End of story!
And I would believe about 3% of what Shearer says anyway. I've yet to see any motors of his prove their worth.