Just a few observations and please pardon me if its stuff you already know.
I have a few Accucell-1 batteries and when I started messing around with Accutrons the main thing I had my attention drawn to was the battery choices and Voltage which is 1.35 as opposed to the Renata 387 which is 1.55. There is a handy table on another site:
Model Mercury type Silver Oxide type 214 387 387S, 394**, SR936SW** Accucell 1 218 343 344, 350. SR1136SW Accucell 1 219 343 344, 350, SR1136SW Accucell 1 2210 388 329, SR731SW*** Accucell 2 230 343 344, 350. SR1136SW Accucell 1 224 343 344, SR1136SW Accucell 1 ESA 9162/4 343 344, 350, SR1136SW ESA 9210 343 344, 350, SR1136SW Omega 1220 343 344, SR1136SW Omega 1300 313 357, SR44 Omega 1301, 1302 343 344, 350, SR1136SW ***Not a perfect fit, but there is no direct equivalent to the 388. ** These are not supplied with the little plastic spacer. Re-use the spacer from your old 387 mercury cell.
You note that for the 218 they advocate use of Accucell and also the 344/SR1136S but the main difference between the batteries is the Voltage ie 1.35 as opposed to 1.55. The use of either battery on a 218 is possible (if not recommended) but if the watch is normally phased for 1.35 and if you then use a 1.55 then it can lead to double indexing on the index wheel. Some repairers re-phase the 218 to use standard Renata 1.55 cells. I suppose what I am saying is replace like for like as if it has been re phased and you put an accucell in then it could lead to a problem. I have a few movements that are humming nicely but even though they are only movements without cases I always check them out with an accucell.
The 214 has a similar sort of choice, if you buy a Renata, the 387 is shown on the package and it has the black plastic spacer disk on it but the positive side of the battery shows the number 394 and it is 1.55v.
I have just returned my Accutron (bought in May) to the dealer I bought it off because gold on the case and crown was literally rubbing off. It looked great when I got it but it had obviously been brush plated to give it a thin gold coat. Give the guy his due and the benefit of the doubt he appeared quite surprised when he wrote back to me after inspecting it and agreed that it was not acceptable. He offered to source a replacement case which he sent pictures of and I have accepted. It makes a nice change to get customer service - I had expected a bit of a struggle.
Anyway its nice to see the hummers getting a bit of attention. Lee put me on to the Stereo Microscope which has made a great difference for examination of the index wheels. They are not easy watches but definitely have less bits inside that the Mechanical ones :D
Cheers,
Vic