Greetings David, Im Dave as well, and as two newer green beans, I say we take over!!
As far as gaskets and shower heads, keep in mind CLEANLINESS...
Clean threads, Clean Surfaces, and Dont overtighten anything!!!!!(too loose will leak and be obvious)
When working with fittings, a little water will help to lubricate parts, and evaporate.
When cleaning, Id use the planets best, most universal solvent to clean.....
...WATER!(distilled of course)
As far as your particular machine, I have no experience. *Certain parts could require sealer/anti-sieze (Lets have some input from the veterans beanos)
Cheers! *Good luck with your operation ...er SURGERY !