Sounds great. They both have the same hardness, so there should really be no problems. Several months ago I found some $1.00 wheels at a local ice rink and bought those. They were soft, so I used them as the middle two wheels but kept my 85a's on the outside. I felt that the softer wheels effected my speed, but I'm not so militant anymore about wheels. As long as the wheels are rockered, (or your frame) you'll have great control and ease with maneuverability.
I think most skaters are used to the constant transition of wheels. I must say that getting new wheels feels awesome. Have fun.
