IMO, it is safest to install the completely stock 1.1 first and let it OTA. I would be surprised if it took very long for the guys here to root it. Froyo is a pretty well understood version of Android.
What you may want to consider is to run the SD card version of CM7 final while the OTA is going on. You may find you're spoiled enough with Gingerbread that you won't want to go back to Froyo.
However, I'm really torn between the two as I really like the native Nook Color reader app. It is, IMO, much better than the Android Market version, though the Market version is serviceable. So far as I know, no one has ported it to run on CM7, much less other phones.
Scott