For the stainless since it goes through a green state I am pretty sure the part as drew has it would snap in half at the filament guide channel being only 1.1mm thick before they could fire it solid, and as mentioned before I think the holes won't size properly.
So this is what I am thinking of trying to have them print:

The holes are sized to 2mm, then will be drilled out to 3mm for a good fit with the pins (pin is 2mm in the picture just to test assembly)
I also filled the filament channel so it is close to 3mm part thickness but left some indents as a guide when filing / milling out the channel to the correct size.
Another thing I am looking at is having a print done in ultra detail then trying some lost wax casting etc..