Definitely fingers first.....I use a Jayhawk Pro jig ( cradle type), so once in place you never remove the ball till done. So even though I measure the thickness of each grip type with calipers ( made a chart with all sizes, including lady size) and layout ball with these lip to edge of hole included, I always punch the finger holes, slip the finger grips into holes while still in the jig, then remeasure span to thumb for each finger to verify before doing thumb. Even if I hit the lines, which I do, some angles such as 1/2 reverse seem to affect overall spans, as well as some grip styles such as semi finger with the raised portion down in a ways, will vary the span slightly. Just want to be as exact as I can. If off , then I restrike a center line (that's why I still use a pencil) to move thumb accordingly to correct if off any.
That's my process, time consuming, but I feel I get paid for quality not speed. Al