Yea thats sound good. Heres what I would do tho, take your manifold, cut the flange of it, and the end you have just cut, put a silicone joiner on it and join it to your silencer (you have basically flipped it the other way round). Get another header, cut it so you just have a straight piece with the flange on it, join this to the old header with silicone coupler tube.
I reackon that should work ok.