I believe we started at -.020 off the lands for the powder charge testing.
As @Creedmoor shooter said, he had previously tested RL23 in his last 6 Creed barrel so we had a place to start. If I was doing load development with zero experience with the cartridge, powder, bullet combo then I have a couple methods I use to find a starting load and “max” load to work up to for the powder testing. The first one is old school, use a few trusted sources, such as published load data, and find what they show for a max charge. Often times there’s a discrepancy in the data between multiple sources, so I just find the average max load between the 2-3 sources then add 1.0gr to it. That’s the max charge I’ll work up to. From there, I’ll load down from that max load for 12 powder charges in 0.2-0.3gr increments, depending on case capacity. This gives you a 2.2gr or 3.3gr window to test. The other method is exactly the same, except I use Gordon’s Reloading Tool to find my max load by inputting my actual case volume, COAL, barrel length, powder, bullet, etc. Gordon’s takes out the guess work and gets you really close. I still start low and work up because it’s never 100% accurate in every situation.
Sorry for the long winded response. I hope that helps and answers some questions. Thanks!