I think the layout depends on what you want & what you'll use the rIB for.
I have a 4m Avon with 40HP merc with console + side seat & bench seat.
I chose that spec on account of having a young family 2 under 5. It's fine for pootling about, but not the best for speed / balance as most of the weight is aft.
I spend most of the time standing up to get best balance / visibility.
I don't think I'd go for the same layout again, but a jockry console would reduce the nice large well I have in front of the current console.