I was going to reply when you first posted but I didn't want to look like a fool or sound like a fool. My wife calls me worse, but we've been married 30+ years so I'm used to her.....
I tend to use Warne Maxima rings, I like Warne rings, for one, they are rigid and 2, made here in the states....
The Maxima's are vertical split and I agree with the previous post, good rings don't need to be lapped...most times, sometimes they do.....
It all depends on how the rings align on the rail. I lap all of them as a consideration because I want to see if there are any high spots and if they are parallel to the tube in relationship to the rail....
You need a length of centerless ground drill rod in the appropriate diameter, some Clover, grease based fine lapping compound and some patience.
Set your half ring set on the rail (in the locations where they will mount to the scope) (that's important because there may be deviations in parallelism and height if the rings aren't set in the final position).....
.....With the half ring in position on the rail, take the drill rod (coated with a small amount of Clover compound and lay it into the ring half and attach the other half (like you were putting on the scope. Then torque the lower (rail mount bolts to the specified torque the ring mfg, specifies (or 35 inch pounds) if no spec. Take the top mount bolts and snug them so the rod in the rings is still able to move both laterally and rotationally and spin it a few times while moving back and forth, just a few times and then remove the top bolts and the side bolts, pull the half off the rail (making note where the rings are (I use a fine paint marker to mark the spots). Remove the opposite side as well but keeping in mind which side goes on the right and which is on the left (I mark them, again with a paint marker) and clean the lapping compound from the inside of the rings. If there are any high spots or misalignment, you'll see it right away. No high spots and no misalignment will result in nothing removed.
It takes (usually a few times) to correct any high spots or alignment issues (if any).
It's important to record the exact mounting spot (on the rail) and the respective positions of each half of the ring....
It's also important to have the base bolts torqued to spec when lapping...
The rings have to be secure to the rail but loose in relationship to the drill rod.
That's how I do mine. You don't remove much material, it's more of a gage as to the parallelism of the rings in relationship to the optic and rail and to a lesser extent, if there are any high spots present.
When done you mount the scope (with the rings in correct relationship and exact placement on the rail as when they were lapped and torque the lower and upper mounting bolts to manufacturers spec, For Warne it's 35 inch pound top and bottom....
Again that's how I do it and I may be FOS but it works for me.
Finally, don't guess at the torque values. Use a inch pound torque wrench or a FAT wrench. I use a dial type Snap-On inch pound wrench and the correct drive socket... Too much torque will deform the mounts and cause misalignment and too little will to plus allow the scope to move when the firearms recoils.
Hope that's not too confusing.....