I am wanting to build something akin to the underbed storage one would
see in an RV. Mattress on a flat board, with a handle of the foot of
the bed to lift the platform hinged up at the head of the bed...and
underneath is storage...the storage area is marginally smaller in
perimeter than the mattress and maybe 12" deep..(the depth will be
determined by the total height, including the mattress thickness)

I am wondering what kind of lift supports to use. I've found something
at Rockler, and one is called 100 and one is 150 and I don't know if
that refers to pounds it can support...

Any input, advice will be appreciated.

This bed and underbed storage is being considered for a weekend
getaway place, so space is a premium and I'm thinking that bed linens,
pillows and blankets can be stored under the bed.

Thanks.
Perry