I think you all are focusing on losses that refer to PTO power. PTO power is all gear ... even so tho, on HST the hyd pump is turning and giving small parasitic loss. You get larger losses running thru the HST trans driving the wheels. Accepted figures are 90% engine power to the axles for gear and 80%+ for HST. HST has an esp hard time driving a load at speed because of very hi pressure and hi drive swashplate angle. HSTs have special provisions to cool them due to the increased losses.
hey gary have have a jaspar 400 in my 85 k20 with 40k on it old days lol im in my mid 30s
I know nothing about HST never had one. If you want to pull a 2-12 plow with either one of the two tractors you mentioned I think the only thing that would impeed the process would be lack of traction not power. My old NAA 2wd tractor pulled a 2-12 plow with no problem and it is only like 20 / 22 hp not a lot there, but it did have R1 tries and they make a lot of difference for traction. 4wd in the new tractor would help a lot with R4's to be sure but I could not be sure ask the dealer.
When I looked at LS tractors, 29 and 24 hp 2 years ago, the dealer said having a 29 hp hydrostatic would be like having a 24 hp geared. I bought a used NH TC30- saved a lot of money. Just passing on what he said.