I've been aligning my all my cars for over 30 years using an inclinometer and tape measure with excellent results. My '88 190E 2.6 front alignment adjustments - eccentrics on the lower control arm mounts are just like my 1976 Cosworth Vega, so there's nothing special about the front, but the rear may be a different story. Alignment shops have great equipment, but the techs are clueless, and I have specific settings for all my cars that are different than the OE recommendations.

It sounds like your car is a so called "net build" i.e. there are no adjustments other than to install offset "crash bolts". My '91 MR2 is like that - no camber adjustment, but caster and toe are adjustable. The OE camber is minus one degree, which is okay, but I adjusted caster (adjustable length drag struts) to the maximum, equal on both sides, that was available within the adjustment range - about six degrees.

I adjusted my '88 190E 2.6 to maximum negative camber and postive caster equal on both sides, available with the adjustment range, which came out to minus 3/4 deg. camber and plus 10.5 deg. caster. I never used a spreader bar for the toe adjustment and shoot for total toe-in of about 1/32". I think the idea behind the spreader bar it to take up any play in the joints.

I recently had to replace the tie rods and center link due to joint wear. It took a few tries tweaking the tie rods to get the 1/32" total toe-in with the steering wheel dead centered driving down a road with minimum camber, and since all the joints were new, there was no play.

With the settings I use, wear across the treads is very even with no indication of any abnormal wear. Typically fronts wear more on the shoulders and rears more in the center, but 7.5K mile tire rotations evens it out over the life of the tires.

Duke