Looking for feedback on electrical plan for studio

You will need your line out there to be a very heavy gauge wire or it won't hold up for that long of a run. All your lighting needs to be LED for sure.

On your studio equipment...are you going to have amps for speakers? Also, have you considered the amount of heat generated and keeping it cool in the warm months? Even a window AC can pull a decent load and if you only have 30-40 amps to work with that doesn't leave you much for gear.

I'd also be concerned about having all your mixing and recording gear on one circuit unless you really do have just a couple things like a laptop and a few accessories.

It's more of a rehearsal studio, less of a recording studio, so there's really only a few powered speakers, a bass amp, an analog mixer, my computer, some LED lights. We're not going to do AC. I've re-drawn the plan to have two circuits and I think we'll go with that. I talked to my handyman friend who has done electric for us in the past, he said we should be fine running it on two 15 amp circuits, one for outlets, one for lights. I ran all our gear through a kill-a-watt meter and nothing was registering very high at all, I'm guessing it will be fine.

Here's the new drawing:

https://image.ibb.co/evBpQk/Full_Size_Render_3.jpg

I like the new drawing with two circuits. I've had issues with other stuff on the same circuits as the audio and video gear, wierd noise and interference.

Don't skimp on the wire out there though!

I'm going with two circuits, one for lighting and one for outlets. Is it ok to run NM romex wire right next to each other in the same conduit for parts of these two circuits? Could that generate possible interference?

I think generally you want to avoid wrapping them around each other, but the big thing is not to include any sort of data cabling in with your power run.

I won't really be able to get them totally unwrapped in the conduit, so there will be some points they probably cross over each other, but not twisted or anything. That should be alright?

Yeah, they'll be fine!