Think we might have different ideas of what these positions need.
No.6 - holding midfielder who can protect the back 4 and dictate the tempo of a game.
No.8 - box to box midfielder, high energy, ball winner
Gana has no passing range and Wilshere is virtually immobile
Fair enough, those are traditional roles, although I don't think a #8 is typically a ball winner. I was thinking of our guys and Silva's formations.
If Sliva plays like he did at Watford, he often didn't use a holding #6, like Morgan or William Calvalho. He played a lot of 4-2-3-1. Both players in the middle went back and forth.
Gana's going to play, as he's about our best player. His best position is as a ball winning defensive midfielder. Just a different role in the 6 position. Mix in a box to box player with him to help move the ball up the field, and we are good.
Honestly, I could also see Silva/Brands getting another good DM that can pass, pushing Gylfi up the field farther, buying a left back that can get forward, a CB that can pass, and playing out of the back. Width provided by the outside backs, Lookman/Walcott as inside forwards, Tosun up top.
But either way, whoever that CM is that they bring in is going to dictate a bit of the style we play within the two formations Silva usually employs.