Outdoor Atmospheres SFX - Fantasy and Realistic

My name is Olivier Girardot, I am a music composer and a sound designer. I have 3 Packs selling pretty well on the platform:…livierGirardot

I am planning on uploading my next SFX Pack: “Outdoor Atmospheres (SFX) - Fantasy & Realistic” which I will probably sell $20 like my other packs. It will include forests, swamps, deserts, ice lands, dragon lands, mountains, magical plains, haunted cemeteries and forests and so on.

I have a few questions for developers who might be interested in such atmospheres.
1- Duration: in some cases my loops go up to 10 minutes. Is this too long ? What is the ideal duration ?
2- In addition to “ready to use” loops, would you be interested in having the loops split in several layers so you can manipulate/recreate the atmospheres to your liking ? Taking in account that this might raise the price of the pack by 50% ?
3- Does it make sense to include both fantasy and realistic soundscapes ? Or should I separate them in different albums ?
4- Is $20 a good price (I invite you to refer to my other albums, because I don’t know the specs of this pack yet).

If you don’t have time to reply to the questions above, you can maybe choose your answers from poll that I have included bellow (it’s my first so i hope I made it right),

Thank you so much for your help !