Hello, I would like some advice on a maverick 88 conversion. I just ordered some wood furniture, duck head grip and corn cob forearm, that is intended for a 590 shockwave. The forearm is to be used with a 6 1/2 or 6 3/4 tube. So i ordered a 6 3/4 tube from midway usa. I also ordered a 18.5 barrel. Is there anything else I might need to accomplish this swap?