In my experience the HK traditional roasted teas are over-roasted, which means re-roasting is probably not advisable, maybe a slow waking up as done for Yancha sometimes: Before the tea session the leaves are gentle warmed on a paper over a source of heat.
You can tell when teas are not oxidised sufficiently and then heavily roasted by looking at the brewed leaves. There should still be some green and red tones come out. Most HK stuff I had was deep brown, almost black. What could help with this kind of tea are clay jars, wax sealed, which might take of some of the edge, porcelain will probably accentuate it.