Well time for an update...
It was tough getting the front main seal out due to the gasket cement they used but I got it out. Then I found a significant problem. The spacer ring was broken; it actually looks like a piece was missing. I hope it didn't do much damage clunking around in the engine. I'm planning to drop the oil pan to replace the gasket; maybe it will be there. I'll post a pic of the broken part. Makes me glad I went the extra step of replacing the main seal. I used the whunter cup tool method described in the DIY Section; it worked great and I would have screwed it up if I hadn't read the article.
I ordered a used harmonic balancer. The old one was pretty "wollered out". The crank shaft felt like it was in good shape--no noticable rings or wear. I guess the softer balancer absorbed all the wear.
I've read a number of posts on aligning the dowels and will do that part this weekend. I have four sets of dowels on hand in case it take a few tries. FYI--the new dowels from MB are beveled on both ends and seem to be of a higher grade. They're kinda yellow like Grade 8 bolts.
I don't think I'm going to use Loctite on the 18mm bolt, probably just Antisieze. I'm planning to use assembly grease on the dowels but I'll use Loctite on the capscrews that hold the pulley on.
I've been trying to locate a big torque wrench; mine only goes up to 150 Nm. I'm thinking about using my 18" breaker bar and my 200# body weight. That should get it close to the 270-330 Nm spec (1.5ft X 200lbs=300ft lbs = about 400 Nm). Then I can go to a shop to check it.
Updates to follow...