Sometimewoodworker said:
You would have to drill clearance holes first so it seems that it is the slowest method and most error prone method, just look at the woodpecker jig reviews with each hole needing about 5 passes, I don't see any reason that a pattern bit would be any better or faster.
I’m with you on this one. Somethings work well and somethings just barely work at all. That’s where the copy bit for this application comes in. It’s a painfull experience if you’ve tried it and I’ll never go back there again.
If it’s only one or two holes, you will persevere, more than that and it’s just becomes some exercise in self flagellation. Just chuck a 20mm bit of your choice in the router and go forth.