Donstil-nl
macrumors 6502a
I'd be really nervous about installing it now on a dev account that's going to expire. Upgrading from WatchOS beta 1 to beta 2 required installing a new profile, which is only available through the developer portal, so there's no guarantee that you'll be able to move past beta 2 when the dev account expires if it's necessary to install a new profile each time. Additionally, for iOS betas, at least, the betas have an expiration date, so I think there's at least a decent chance that you could wind up with an expired WatchOS beta and be unable to upgrade or downgrade.
You know that you can download that profile from any site right?