I was fortunate to find a yard who has extra space and a wide lift, who offers multihulls storage for the same price as monos (based on LOA vs double price of monos). So this is the seconfd year I've stored with them. Great folks, BTW at Captains Cove in Bridgeport.

Until then I also stored with mast up, but folded (14 foot beam) on the cradle, so about the same beam as many monos and power boats of the same LOA.

This boat is fairly heavy at 12,000 and on the custom steel cradle with extra boat stands under the folded amas has proven stable enough for the wort of winter storm crosswinds.

For Tom: I also stored my prior tris with mast up, folded, but they we're much lighter. I added a guy line on each side to stabilize them. I'd use the main halyard on one side and the spinnaker halyard on the other. I'd add a tie line to extend the halyard to something immovable or very heavy such as another boat's cradle (not stand, and yes I'd ask for the owners permission) or something anchored into the ground e.g. Rail track.