I've visited all of the 22 claimed highest peaks above 2,000 metres except Jagungal, which remains elusive as it needs more time and planning due to its distance away and isolation. The others are achievable as day walks; many can be done in a day or less, or as a series, due to their close proximity.
Why would you want to 'do' Jag in one day????
That country - worth 3 or 4 days!
(Note that Parks has closed the J Wilderness for a few weeks to shoot feral. Fair enough.)
Cheers
Roger