A while ago I was at a springcompany to get some springs and in my investigation I did see wave springs:
http://www.amatec.nl/webshop/golfringenI did get some with a 4.92 hole and 6.15 outside (the closest to 5mm they had). I dremeled out the 4.92 hole to 5mm and cold it fit rght under the bearing where you place the shims for setting the endplay.
The spring has a thickness of 0,76mm and a springrange of about 0.4mm
Just shim it out to +/-0.5mm endplay and place this wave spring als the last shim. The thrust bearing will always be under a small pressure giving it a maximum life but there are more advantages like a fast and easy endplay setup and a beter lining out the gears when mounting the engine.