Slab table hints

Hello all, This weekend Rockler in Cambridge MA had a sale where their slabs were 50% off. I picked up two slabs of Japanese Cherry. (See pix below) They are not bookmatched but are close enough. The interesting part is that one of the boards is upside down in the picture and the chatoyance forms a nice S curve across the pieces. I think I will keep it this way rather than having an “m”. I have made other tables but this one is a bit unique so I need a little help.

1. What is the best way to store these pieces for the 3-4 months it will take me to finish my current projects? They are currently in my basement perfectly level 20” heavy duty shelf brackets supported very 2 feet. I sticked them with 1/2 poplar.

2. Although the boards are flat now I am concerned that over time they will start to have a mind of their own. What are the best methods of spanning the boards on the bottom side that keep the tops relatively flat but also allow for movement?

3. Has anyone worked with Japanese cherry before and does it darken over time?

4. I love the look of a BLO finish on cherry but I am concerned that it will not be enough protection on a dining room table. Everything I have read is pointing me to a rock hard varnish. Can I use an oil first to pop the chatoyance?

5. The boards are 10’ long. I am trying to decide if I should keep them that long or cater to the more popular dining table length. I just hate to cut them. How much of a market is there for longer tables? I may have customer already for the 10’ but if not I need a backup plan.

Thanks for any help you can provide

Tim