- I can then go straight for the conversion to a 32 bit TIFF, without doing any toning [as all of that can be done in LR]?
- or is it better to do basic toning in HDRpro, convert to PS and go back in History to the state were color profile was assigned?
You want to simply save out the 32-bit TIFF. When you select the 32-bit option, you don't really have the ability to do any toning. You can change the gamma slider but I'm pretty sure that only impacts the file preview and don't actually impact the full 32-bit rendered file.
As far as the LR4>CS5, you'll want LR4 to do the render.
With regards to your complaint regarding LR4>CS5 popping a a new saved TIFF from Edit In, yes, that's what happens with your LR and ACR versions are out of phase. When out of phase you have to have LR render the file and this requires saving a TIFF prior to LR handing the file off to Photoshop. When in phase, LR just hands off the file to ACR to render and a TIFF file isn't saved. But, I don't thing that apples to HDR Pro...and yes, Photoshop insert a default name and save in the last folder.
As far as working with 32-bit in CS5, can't really tell ya since I'm using the CS6 beta.