Dogbone mount improves gear selection due to holding the engine more steady, thus the cables aren't moving about and the adjustment isn't changing as much.
Even so, I'd be concerned about a 10K car with a grinding box even with the standard mount as it shouldn't be worn too much on that mileage.
But its a proven fact that thick hypoid oils on worn gearboxes prevent the hubs in the syncromesh from rubbing together as they should. This causes the dog teeth between the gears and main shaft to take a longer time to match each other so you get the classic VW/Audi second gear crunch on frosty days.
Thin the oil and you help solve the problem.
Still baffles me that VW/Audi haven't sorted this since the first MK1 golf "020" boxes from 1983!