I already posted my army and reserves but i couldn't find the page, so here ya go
Your current group of heavies is sufficient when paired with the Medium tanks with Ace (since it buffs evasion), IMO.
Croc, Tiger and E-100 if you can afford the high cost (which you use would depend on incoming enemy tanks IMO) plus the Panthers and maybe a Downfall artillery if you're worried.
That Stridsvagn with a range/damage/rate of fire build would be a nice pick to second line behind an evasion build heavy tank. Stack up the secondary evasion modifiers high on your front line units and keep the Strid in a support role as long as possible.
Damn... I want that Suppress skill on an artillery piece. Too bad they don't do dual passives on tanks.
Strid got bigger attack range than most of my TDs, only jagdpanzer 4 with skill active has bigger range
In most situations, heavies are nothing but a drag on my platoon.
Main issue with Strid I've found is that she's typically targetting and debuffing the enemy heavy tank while that enemy tank destroyer or arty remains far behind it and not getting debuffed.
I've found Strid more useful for debuffing enemy commanders' accuracy (shred and Strid's debuff do work on enemy commanders). Especially those damn abyss crystals that take forever to die and thus having them be debuffed for the duration of their freakishly long life is very nice. Also nice vs Siegfried where the most threatening (the only threatening) thing about her is her DPS.