Trim and grind cowl halves to fit. I needed to remove flange material to yield a nominal 3/4".
Clamp and drill nose section of halves using #30 drill, cleco as drilled.
Verify dimensions and uniformity of inlets.
Remove clecos.
Attach 1/4" spacers to top cowl.
Mark a 3" reference line on fuselage using a piece of.025 aluminum sheet sheared to 3".
Level aircraft using digital level.
Attach plumb bob to spinner disk and adjust to level perpendicular lines previously marked on disk.
Create a level surface on floor using a 6' level.
Clamp top cowl in place. Adjust cowl to center and level. I used multiple points for verification; ie cowling split line near spinner, top of inlets, and outside cowling edge.