All of the Alpha freewheels were excellent. Suntour's best imo, shifting under considerable pedaling force is a reality with these and there is NO chain "skating" using modern chain.
The Alpha 5000 shifters and derailers work VERY well as indexing components as long as contemporary chain is used.
I would definitely use 9s chain with any Accu-7 shifters because of their generous over-shift free-play when shifting toward larger cogs. This will prevent unwanted chain contact with adjacent larger cogs. This may preclude use of say a Stronglight 93 or SR Apex crankset because of the chainring spacing (though smaller rings can have their teeth bent a half-millimeter or so to prevent the chain riding between adjacent chainring's teeth).
For the 121mm rear of my 1974 PX10LE, I slightly modified the axle spacing and wheel dish to allow a 7s freewheel on a 124mm spacing width, and ended up with a
very strong wheel by exploiting the redundant axle overhang dimension on the (originally) 5s hub. I kept the axle overhang past the face of the smallest cog down to about 3.3mm and it adequately cleared the frame using 8s chain after I massaged the axle-position hardware with a Dremel and kept the smallest cog down to 13 teeth or so.
Note that the 7s wheel shown was for use with Campag 8s shifters and derailer, not Suntour, but the 7s freewheel worked well in this application.
Also, since you will be using only a 6s freewheel, a very strong wheel can be built to 121mm spacing width if the axle spacing keeps the locknut from protruding much past the face of the smallest cog.
