I hear what you're saying about the overhaul. I have my fingers crossed over mine which should be done by the end of the month. I would not have done the overhaul but it needed a lot of key-tightening. In the meanwhile I'm enjoying my back-up Selmer USA but I do miss the VI. At least I backed off of sending it to a guy who was going to take it all apart and re-shape the upper body tube 'because all of them in this series are pinched up top'. I don't care if they are - I like it as it is.
I'm sure you'll get your sound back but honestly, I don't know how you can cope with the sax being different plus several new mouthpieces at the same time - not something I'd try, but hopefully it'll work for you. To me, the mouthpiece is the 'constant' around which can revolve various horns. I have found that after an overhaul or with a different sax, it takes about a month of heavy playing before you 'auto-adjust' to the differences and return to your sound and/or adapt to the differences.
I'm sure you'll get your sound back but honestly, I don't know how you can cope with the sax being different plus several new mouthpieces at the same time - not something I'd try, but hopefully it'll work for you. To me, the mouthpiece is the 'constant' around which can revolve various horns. I have found that after an overhaul or with a different sax, it takes about a month of heavy playing before you 'auto-adjust' to the differences and return to your sound and/or adapt to the differences.