I have a brewmaster offspec for old content soloing (but not too old, otherwise I use my mistweaver main spec), and I was shocked by how poorly I fare in the Proving Grounds, struggling with silver, though occasionally beating it on a fluke. Gold seem way out of my reach.
My soloing skills are so that during patch 5.3 I managed a Zul'Aman bear run on the second try with full season 13 stuff (ilvl 489), and I could have done it on the first try if I hadn't got lost (I was really discovering the instance). But on the other hand, I can't get Magmaw below 78% before wiping.
So my question is, is it worthwhile to stick to Proving Grounds, or would I be better off in some Cataclysm instance to train my soloing skills?
Is there any boss of intermediate difficulty between Zul'Aman timer and Magmaw, so I can try a smoother solo progression?