Let's back up a second. The UCAs end up being installed so on one side of the car the welded piece is to the front. On the other side of the car the welded piece is to the rear. The way you have them laid out in your first pic (forget your labels for now, just look at the basic pic) is correct. Or you could turn the picture around 180 deg and install them that way. It doesn't matter. The dimensions that FFR gives are an approximation to get the car somewhat close to OK w/o actually doing an alignment. They do this because people are usually installing the suspension many months (years?) before it will be driven. Honestly I would forget those dimensions. I have helped align several MkIVs and you can usually get about +6.5 deg caster with -1/2deg camber w/ the stock parts. This isn't terrible but many of us prefer the feel provided by +8deg or so caster. (A quick aside; caster is the angle of the spindle when looked at from the side of the car. More caster means the spindle is leaned backward at the top more) So to get that extra caster the sleeve on the rear of each side of the car needs to be shortened. I usually machine away the round section on each end. It is simply an easy guideline to machine by so no need to keep measuring as metal is removed. BTW I am happy to do this for anyone who needs it on my lathe. Email me at craigstuard at comcast dot net with FFR sleeve as the subject so I don't delete it because I don't recognize the sender name. I don't charge to do this but ask you to stick a $10 bill in your box to cover the return shipping.