I will check to see if I can find part number but I have forever had a set of saddlebag packs that perfectly fit in the saddlebags. Just a cotton type (?)or maybe a light canvas that zippers and has handles attached. This is however for the older style saddlebags. Don't have anything for the new bags yet and figured I would use the ones I have if I had the need.

 

If you are not riding two up, and it depends which seat you have, I like a Saddleman Tail Bag.

https://www.saddlemen.com/index.php?...-bag-universal

 

I found what I was talking about when I used "harley saddlebag bags" as a search phrase as well as a Saddleman 4 piece set that I really like.
Saddlemen 3501-0760 Large Saddlebag Packing Cube Liner

 

Something like this worked well for me and my RK. Doesn't need to be Harley, just similar. This and your saddlebags will treat you nice. Two up, on the luggage rack. One up, on the passenger seat.

https://www.harley-davidson.com/store/touring-bag

 

 

They also have the rolling version. Convenient if you have the saddlebag liner bags. Just throw them over the handle and roll everything to the hotel.

Place it on the back seat, if going solo, and makes for a convenient backrest.
https://www.harley-davidson.com/stor...ng-touring-bag

 

Nelson-Rigg makes some nice luggage.

I have an older luggage bag that mounts to a backrest that I used on my old Road Glide.

 

I have a Dowco tailbag set up I use either on the luggage rack or against the passenger seat rest and my backrest, mounted on passenger seat. Seems ok to hold all my crap if I pack smart. My brother gave me an older Nelson-Riggs (although brand new!) rear bag that I haven't used yet. Do some searches and you'll find something!!
Good Luck!