Valve Noise

[83 300D]

Trying to track down the source of the white smoke I get on start-up, I did a number of things to the car. I checked for fuel leaks, checked the glow plug relay and eventually replaced all 5 plugs although only one seemed a little less hot than the others, I ran Sea Foam through using the Diesel Purge method described on this forum, I took the injectors in to a Bosch shop and had them tested and had two rebuilt, and I adjusted the valves. Fix the problem? No, it smokes now worse than it did and is harder to start. I figure I need to go over everything again and see if it's all tight. I don't expect anyone to be able to diagnose that online. However, here's my concern. When I checked the valves they were all tight. That is, my feeler guage wouldn't fit in the gap. I did the adjustment and now have more valve clatter than before. Does this make sense? Is this normal? If I adjusted them too loose how would I know? Other than being hard to start and smoking on startup it runs fine. Fuel economy seems to be down just a little, though.

Thanks,
Mark