welding hastelloy C22 to 304L or 316L stainless

[hawklike1]

We are undertaking a product development project that welds .75dia x .19thk inserts into stainless steel and then machining a precision o-ring seal in the hastelloy. Our current intention is to machine a 30 degree bevel on the stainless counter bore that will nest the inserts. We have extensive stainless experience and some orbital welding of Hastelloy C22 tubing, but no hands on experience of C22 to stainless. Can anyone provide recommendations process paramenters including filler rod?

Big thanks,
Max