Personal opinion here, based on experience. I'd spend the money to get the HST and get used to engaging the PTO by throttling to idle, flipping the switch, then bringing back the RPMs as needed. Based on experience thus far, I won't buy another gear machine. The 'lost horsepower' argument due to HST simply doesn't hold water in the everyday world.
You'll find the HST soooo much easier when creeping along fence lines at full RPMS on the cutter. Much more control than stomping a clutch and shifting to back up and get a spot you missed.
I spend about 50-hrs a year just on cleaning fence rows after haying. And then add pond dams, and blackberry thickets, and rural ditches. The HST is much better than any clutch, and I've tried them all.
Please post back your experiences so we may all learn as we look over your shoulder.