Have you used a lot of indirect MG fire? Especially in behind any massed charge. You have lots of MG's over 20 when you include your Company of Infantry with its Halftracks. In Poland HT's can be used within reasonable range. IF the Poles armour is dealt with shut off the main guns of your armour and having their MG's join the fray will help too. (Remember to turn the Main Guns on afterwards)
As for an assault at this period lots of pioneers and artillery some large calibre but make sure you have smaller calibre with smoke capability. Ensure the support units make the initial assaults and give them good smoke coverage. I also like to have a Motorcycle Platoon or two to go though once the minefields etc are breached and lead the way and recce the objectives.
As for the addiction, welcome to Club buddy!!
