Advice for selling comics. Large collection from 80s-90s

Hey yall just wanted some advice for those with experience in reselling comics. Have a large collection, but I'm looking to use it as a source of inventory.

My main questions are

1. When one has a complete or almost complete series is it better to sell it as huge lot or break it into smaller lots. 2.Any advice on shipping large amounts of comics at once.
2. What mailers do yall use (u.s only), been having trouble getting a good size
3. What to do with random comics of no value or heavily damaged comics that atleast be a scrape back.

Thank you for your time if you read this,