I just got a Fender Bassman 400HB with a Bassman 410H.

Because my room is not very big I have to stack it on my other rig until I can take it to our rehearsal room. The other rig is an Ashdown MAG 600H with a MAG 410t deep.
What I intend to do is stacking them this way:
Ashdown head
Fender head
Ashdown cab
Fender cab
floor
I'm a little scared the Fender cab might break under the (a little heavier) Ashdown cab and the additional (also slightly heavier) head. But I have to put the Fender under the Ashdown beacuse the Fender's surface is a little larger.
Will it hold? Is it a real risk or am I just overreacting? I'd appreciate some views, thanks.