hello neighbor in the blue grass what parts are you from
Ran a customers turf tiger a couple weeks ago with the 26.5 EFI Kohler and the 61" deck and for me it seems underpowered. the 29 may be ok on the 61" deck but wouldn't go smaller if you are planning on heavy grass and pushing the mowing speed.
The commercial cutters in my area replace the mowers about every 900 hours and it doesn't matter if it is Kohler, Kawasaki, Briggs, Or Honda.
But first, a disclaimer: I'm not trying to sell my mower; I'm just writing this for comparison. The Turf Tiger II/61" deck/Kohler 26.5 EFI setup weighs in at 1540 lbs. The Tiger Cat II/61" deck/Kohler 29 EFI is roughly 150 lbs lighter (at 1288 lbs). The Turf Tiger II here is also pushing 16cc hydros while the Tiger Cat II uses 12cc hydros. All that may explain the bog you experienced. While I'm a mechanic, my experience is in flexographic printing presses, laminators, slit-down machines and support equipment. When it comes to mowers, I'm just a homeowner with a large yard (so I guess I'm ending with another disclaimer).
I was almost ready to pull the trigger on this but I am starting to second guess the Kohler engine. I feel with the 3.5 to 4 acres of land I am going to be mowing that I should get the 61" deck. I just feel the Kawasaki is a little under powered for the 61" deck. I'm thinking abut looking at the 52" deck with the 23.5hp Kawasaki engine now but not sure if this will slow down my time for cutting more