...
Do also mind that su76 without su85 or infantry support has no spotting so effectively cant use its 60 range...
That is is incorrect.
The vet 1 ability "tracking" increases the sight to around 49 and provides mini information to range 70, allowing the unit to barrage with more accuracy and see in the FOW. Apart from that many soviet units can deploy flares making easy foe the unit to spot without placing the spotter in harms way.