Sorry, for not talking in thread more! Can't wait to use the new 3d feature!!!
Also, I might try learning the Sa-4/5 soon.
SA-75M Dvina (SA-2B/F) should be learned first. It is the cleanest system.
S-75M Volhov (SA-2E) is where you have all the extra features/options, should be learned 2nd.
S-125M Neva (SA-3B) has a bit different display layout, but more automatism compared to the Volhov.
2K11M1 KRUG-M1 (SA-4B) is similar to the Neva, with less display, more capability against ARM.
S-200VE Vega-E (SA-5B) should be learned the last. It is the most complex one depicted in the sim.