You're making a monthly or twice monthly visit to T5 then, so I think you would find the First Lounge a good place to wait, given that I guess some connections are a bit extended. Few regular Flounge users enjoy going upstairs and BA seem quite deliberate in making the differential in the two sets of lounges evident to keep GCH in their place! Five hours in Flounge is a stretch, five hours in Galleries Club is verging on punitive! If you want to visit Flounge to see what it is like, just drop me a PM with some dates.

Gold Priority Reward is fantastic, a major part of the GCH perks, particularly for forcing flexible Reward Flight Savers in Europe at a competitive rate even if you are not Avios rich. That along with access to good seating must be a good aspect of Gold status. Not sure there's an advantage on Silver for WT, however, particularly at short booking since at T-72 it becomes a free for all status passengers anyway.

From your previous experience, the occasional upgrade from WT to WTP should happen with Gold status, particularly if you tie in your GRU with end of the week / student traffic, when GRU gets overbooked.

And my belated welcome to you, BrazilTraveller78, welcome to the British Airways forum on Flyertalk.