My L4060hstc has been good for me. Front axle isn't the strongest, but I believe they make the jump to the bigger axle with the L4760.
Up here in Colorado we are down 20% on HP due to lack of oxygen. I wish for more HP roading the machine & mowing with a big flail. Fine HP for the traction. Considered upgrading, but don't need more power that much.
The 2 speed HST+ is worth it. Medium range covers almost everything. Toggling ranges means you rarely have to shift the clunky manual unsynchronized gearbox every manufacturer has on their HST machines.
I don't find much value in cruise, auto throttle, stall guard & other fancy HST+ features. Try them occasionally, but turn them off again. 2 speed action makes up for it though & is worth it all on its own.
Load the rears or get wheel weights, but you should do that on most any machine.
R4s work fine for me. Good compromise between carrying capacity, traction & durability. I don't have mud to deal with & am on more puncture prone territory. R1s ride rougher & rear things up more. I'm rarely traction limited unless I'm in snow. Might try R12s on the next machine if that ever happens.