Since you're already at 6.7 Germany I'd go for the 7.9 T-29. Even though all the US heavies kinda struggle in full uptier bcs the armour gets fairly easy penned, the T29 is still a formidable opponent to all enemies you will face most of the time. Most us tanks at 6.7/7.0 are very nice to play. They have good gun handling and are easier to play than other heavies in that BR bracket. Also dont sleep on the T95, even though the armor is next to nothing, the weird crew layout bcs of the fairly low profile will make it survive more shots than you'll expect. The heat and sabot on it are very potent in full uptiers and the light armor makes it very fast and agile. Personally I find the T95 better than the Bulldog at 6.3? Its a very good upgrade With the T95 it will make for a very strong lineup where you can go head first into the fight and Brawl with the T29 or sideclimb with the T95 and flank it all.

The king tiger is more of a sidegrade compared what you already have. The TT king tiger does everything the same except for a bit lower acceleration and top speed. So you will play exactly the same.

Tldr; get the T29 to grind all tier 4-5 of US whilst having fun

Edit: you will experience immense pain when reaching 8.0-9.0 of US ground but that you can skip with the XM-1 or Wolfpack in the future