I like the concept of the hardhitting jackson and I'm ok with the RNG.
But you could nerf the damage from 240 to 200 and give the jackson a deflection damage of ~100
Shock Rifle Frontline Tactics (Free)
Shocks troops, flame barrage and the IS-2 makest his very good against infantry and heavier tanks alike
Guard Motor Coordinated (free)
Guards are currently not all that great but have utility. the 120mm is amazing vs OKW trucks and campy players. Mark vehicle makes tackling any heavy tank a lot easier(35% extra damage) and the 85 provide a lot of shock power
Then for teamgames I think either one of the ISU-152 commanders or the Counterattack tactics
Advanced warfare is good for 1v1 too and will be given to you in 48 hours
handheld at should be defensive in my opinion but as it stands down you can chase down tanks at long range no problem with schrecks.
So reduce long range accuracy or remove the ability to heat seek.
Change penetration from 180/170/160
to 190/175/140