I am in the process of ordering more foam for my Battlefoam carrying cases and I have extra space in the tray I am creating. I would like to anticipate Wave 5's release and have slots available for the YT-2400 and VT-49. Does anybody know (or can accurately predict) the shape of foam I will need to have Battlefoam cut?

According to the Internet, the YT-2400 is 18.65 M long by 28.5 M wide, which translates to ~2.72" x 4.2" in the 1/270 scale.

For the VT-49, all I could find was its length (38 M) which is ~5.54".

I could find no reference to the height of these models so I can get the right thickness of foam. Any suggestions?

No one has them, so the answer to your question is, no.

I would just make squares in approximately the right size. Neither ship looks to have anything that needs extreme coddling.

Or you could wait until they're released, and then you could measure one.

Patience young padawan.