Why not do both? For one day cruisers, they can part company at midday (Jamieson) and the remainder can forge on to Bright. In any case, I would consider to do this route anyway, as I have been wanting to for a while now. My preference is for an overnight cruise and get to see the high country in summer.
Cruisn and I did discuss briefly the meet up with the Sydney folk and I suggested a meet in Holbrook and a return route via Snowy Mountains Hwy to Cooma, then down through Bombala on the Monaro Hwy to Orbost (see the flowing Snowy River), then back into to Melbourne. For me, I would suggest this is more of a 3 day tour as there will be lots of places to stop along the way to take in the scenery/history.
Actually, maybe we should define a new category, "Tourers", for those cruises that exceed one day!