I chose to outsource the construction of the manifold. First I took a new gasket to a shop that does laser cutting, and ordered a 12 mm thick steel plate to be made from that ; and then the rest of the work is being done by a friend who has a long experience in fabricating manifolds for race vehicles. True it does cost some "dough" but end result is expected to be good. Basically my part is to come up with the flanges at the cyl head and at the turbo ; and then to describe what kind of rpm, boost pattern and such is expected from the engine, along with a truck load of data such as the camshaft, cyl head details & so on.
There are times when it's a good idea to just buy some services and I felt that the manifold construction is one of them. Better use of my own time is to work overtime and save the money.
Well, a funny thing did happen, as I ordered the flanges from the laser facility I was actually hired to work there myself. I guess from now on I'll be making my own flanges when production schedules allow.