I've struggled for a couple years on an economical way to drill bench dog holes.
My forstner gives the cleanest and tightest results, but doesn't do well on thick tops.
I never got tight results with a spade bit; which makes holdfasts tricky for me to set.
I stumbled on this method and it works very well for me:
1. Drill with a 3/4" forstner bit down 1/2"; enough to start the hole.
2. Switch to a 1/2" twist or brad point bit, and drill through the bench.
3. Switch back to the 3/4" forstner and widen the hole. The clearance hole prevents heat and chip build up, and keeps the bit cutting cool and efficiently.
Quick, tight, effortness.