LP storage advice please?

You might consider putting the LPs on shelving racks in the storage unit. That will give you access to them, you can sort, weed, sell, give away and then decide what to keep for yourself. Occasionally grab some to listen to.

I bought chrome wire shelving, added wheels to the bottoms, this type of thing, look around, various sizes and prices. I had wood shelves with dividers to put on the wire shelves, you would need to add a smooth shelf on top of the wire to avoid damaging the bottoms and so they can slide in/out.

Smooth metal shelves might be better, but they need to be strong, if not: several 30" wide units better than 36" or wider

Get a bigger storage unit.

Have a look at my main virtual system. I have about 2,100 albums. These white cubes come in singles and doubles. They are not expensive. 

Whatever the box or cube system, it is a good idea to shift the records a bit from time to time. They should be store vertically, not lean to the side, yet not so tight that they cling on to each other.

The collection was in my parents' FL condo for 30+ years. Pop had them on some cheap graybar shelving. When I packed them, I made sure the boxes were snuggly packed so they wouldn't shift, lean or sag. 

I plan on using the Kallax system in our next home as the storage solution. The thought however of doing that in a storage unit somehow doesn't seem practical.

Thank you all for your thoughts.

Happy listening.