You may get problems in welds cracking if you didnt use stainless steel migwire as the two different materials could expand at different rates when hot. (I speak from experience on mine) I did a rush job welding up a split on my stianless top mount manifold with normal migwire and its split again
. I will be stainless tig welding beofre i fit the t34.
But your welds look pretty heavy duty so fingers crossed. The rose joint idea sounds good, Maybe i will try that myself as we have a lot of them lying around at my work.
the fannymolds coming along well, has the external wastegate flange arrived yet? What Turbo are you going to be using?