[TangledHeart]

I have a 3 handle shower tub faucet that has leaked for years. I replaced the stems last year, but recently learned that the ones hardware store gave me to use were the wrong ones. I brought in the original, and being a novice, I was under the impression the associates working there had the knowledge to give me the proper replacement parts. Against my better judgement I used the Price Pfister stem replacements that were given to me by the sales associate. It started to leak shortly after and washers have since been replaced twice.
There was a leak on the main water shut off, and since the water had to be shut off for the repair, I decided to replace the washers, or rebuild, whatever it would take to stop the leak. Since there was issues with the diverter, I decided to rebuild or replace that too. THAT was WHEN I realized my gut feeling was correct and the stems were not the correct ones. Before I went to the hardware store, I went online and crossed referenced images and descriptions older faucets and the diverter . I found out the original parts were/are Sterling.
Beings Sterling is no longer manufacturing these faucets, I had to find either an after market repair/replacement kit or find somewhere that still has the parts. I prefer OEM, and found a plumbing supply that carry Sterling parts. Since I no longer have the original stems, all I had to go on was the diverter and the original seats.
Knowing how important it is to have the seats in good shape, I chose to replace the old ones. I cleaned up the inside of the manifold as much as I was able. It didn't appear to be stripped or gouged in any way. I used a plumbers brush to clear any debris that may be left, and blew it out.
I purchased new all 3 new seats, H/C stems with original washers, new diverter stem and washers, and all the trim.
I sprayed a little silicone spray on the seats, put on single layer of Teflon tape on all the stems, and carefully inserted and tighten. I made sure the stems and bonnets were tight, but was careful not to over tighten them.
After everything was in it's place, I turned on the water and it leaked. Something did, but was sure what. It was a small leak, but no leak is acceptable, especially living in So Cal, where we are in a drought.
I have tried everything I know to stop the leak... I've changed washers, trying different styles in hopes one may better cover the seat, if there is possible issues there, I've put a single layer of Teflon tape on all threads, I've silicone sprayed every part, and done it without each. I have kept the openings in the manifold clear of any possible debris, although there has never been any found as of yet. It doesn't appear to have been crossed threaded from the prior instal of the improper stems, but I could be mistaking or just not seeing it. I have looked at the threads of each stem every time I have taken it back out to see if there was any particularly unusual scratches or change in the threads and I have seen nothing.
I am at wits end... I can't stand this leak, and it just plain puzzles the heck out of me.
Is there ANY tricks someone can suggest? ANY suggestions, short of replacing the entire faucet, would be soooooooooooo appreciated. Like most homes built in the late 50's early 60's, the tub is tiled and re-doing it is not viable option right now.

[hkstroud]

Suggestion.

Remove the stems. Make sure the stems are in the open position. Reinstall the stems.

[TangledHeart]

Thank you, they WERE already in the opened position when I installed them. I research that type of information prior. IE how tight, use or not use silicone spray, Teflon tape, etc. Thank you for the suggestion though. ALL thoughts are genuinely appreciated. :)