44.1khz 5.1 Sessions to ATMOS

Hi Everyone

This is my first post here since moving from Cubase to Nuendo, so hello! Last year I upgraded my studio so I can mix in 7.1.4 Atmos for music - I was very fortunate to have my room calibrated by the guys from Dolby here in the UK. I’ve mixed one commercial release, which was a live recording on Blu-ray. Unlike Atmos for film where I understand you guys start with Atmos and work backwards to stereo, for music it’s the other way around, it always starts with the stereo sessions.

I’m currently working on a big session remixing a back catelog - about 8 hours of music. I’ve finished the stereo and 5.1 mixes and I’m now ready to move to Atmos. I have two queries I’m hoping someone can help me with before I get going…

1 - All the sessions were recorded at 44.1. Does anyone have any recommendations how to convert the sessions safely to 48? I’ve experimented with changing the sample rate and allowing Nuendo to convert the pool but for some reason I ended up with a mess. Should this work? My thoughts were to batch export all the stems and re-apply FX when required.
2 - For authoring, I am required to send a single audio file with a cue sheet. This isn’t so easy with Atmos and multiple mixes. Has anyone had any experience with the Atmos conversions tool for joining ADM files into one large master file? For my last live Atmos project, I was able to export a single mix from a single Nuendo session. I don’t want to mix 8 hours worth of ADM files only to find I can’t join them at the end!