"You can only send a file to Topaz as a TIFF, PSD or Jpeg".
Topaz Studio imports RAW as well.
"Since it goes to LR as a TIFF when you press Save (bottom right hand corner)..."
When you press the Save icon (lower right) in TS it saves/overwrites to the original location, nothing to do with LR as far as I can tell.
"it comes back as a TIFF."
Back from where? Do you mean "is saved as"?
Other than that I really can't follow your description. I'm not sure what "send it" means (export from TS? import into LR?). You say you don't edit any more back in LR but you prefer to use LR (?).
I'm trying to figure this out really ;-)
NP. My apologies that I'm not explaining it well. I keep forgetting you don't use LR so I'm not putting in much effort.
LR is main software. I don't plan to import RAW into Topaz. I'm using it as a plug-in. That will rename.
When you send (using the Edit in Topaz Studio command) a file from LR to Topaz, LR creates a TIFF immediately and places it beside the original CR2 - in LR. Topaz syncs to that TIFF in LR. A TIFF because that is the default. I can also choose DNG or Jpeg but that is not critical now. In Topaz there is a "Save" icon in the bottom right hand corner. Not Save As. When you are done with the edits and press "Save" it saves those changes to the TIFF file that is in LR - beside the original CR2.
What I have been saying is if you make any additional edits in Topaz and you press "Save" a second time, those edits do not not show in the filmstrip in LR, only when you export. So 3 months down the road you wouldn't know that there were additional edits applied.
Also if you want to start over by deleting the file in Topaz and sending that same file again from LR it won't open in Topaz.
In both cases I have to restart Topaz.