Upgrade Roamio HD with Premiere HD

My setup is: 2 tuners Premiere with upgraded HD (1Tb) in the bedroom and a basic Roamio (4 tuners) (500Gb HD) in the front room , both attached to a direct ethernet connection and working great.

In an effort to save cost I want to replace the 2 tuner Premiere with a Tivo Mini so I can drop the monthly service charge. At the same time I would like to use the 1Tb drive from the Premiere in the Roamio.

My plan is to transfer all the recorded programs I want to keep to the Roamio and then replace the 1Tb drive with the original HD (320gb) in the Premiere and update to current software. Once updated I would transfer shows I want to keep from the Roamio to the Premiere (space permitting) and then replace the Roamio HD with the 1Tb HD I removed from the Premiere.

My question is: 1) Will this process work?, 2) Will the Roamio use the 1Tb drive without doing anything to it prior to installing it in the Roamio (will it reformat automatically?)? If this will not work, what do I need to do to the 1Tb HD after removal from the Premiere prior to installing into the Roamio so it will work?

Thanks for your help!
John