[Reg]

35 feet wide? That is a helluva wide room. How long is it?
If you have a dry basement I see no problem is using solid wood on the main floor above. A paper underlay may be in order.
I'd also say add a humidfier if you are 20% - are your knuckles not a cracking? Keep the home at 40% all the time the movement will be minimized.