understanding 60i vs 29.97fps (?)

I'm rendering a video project that was recorded thru a Sony FX7 in 1440x1080interlaced. Video format is HDV. Final render is to be a bluray disc playing on a HDTV.

I assume my master footage is in 1080i at 60i which, to me, means it was recorded at 60interlaced-fps (?)

Using my own logic, if I recorded soemthing at 1080i at 60i fps, and my final bluray project is going to be 1080 at 29.97 fps.....would it make sense to RENDER in Vegas a progressive scan at 1080p at 29.97fps so vegas takes the 60i frames and BLENDS them down to 29.97fps?

I'm unsure if redering my bluray proejct with progressive settings will result in best quality playback (?)

It makes sense to me if the master recording was 60interlaced frames per second that my final render would take each odd/even interlaced frame with 60 frames per second to work with and blend them perfectly down to the required 29.97fps bluray playback on a HDTV

Am I way off? please enlighten me. Thanks