MB, like all the other guys said already; no it won't be a problem at all, four bolts and you are ready to go. If the mower seems to lose speed and power and makes alot of squeaking noises from under the engine you may have to tighten the drive belt. Simple to do wrench and a large screw driver or pry bar.
If you drill the Proline for the hitch yourself, use copper tubing or something for a sleeve over the drill bit. Cut length of sleeve so the drill bit will go through, but prevent pull-in on breakthrough and drill the drive belt & pulley.
Kawi 12.5 on my 44 pulls me and jungle jim no problem. I was surprised that it was enough for a 44, but I don't mulch with the 44.
Depends on how large you are.
Most gear drives will pull a well made sulky, however, accelerated drive belt wear, increased fuel and oil consumption should not be overlooked.
Additionally, if you operate the machine when it is hot outside, watch for signs of electrical connection problems associated with the increased demand you are placing upon the machine.
You can try what I have done, and that is replace the rear drive tires with aggressive bar lug type ag tires. Turf damage from tire slippage has been greatly reduced, traction increased, and stability on slopes even without the sulky where all noted to be worth the exchange.