.....or cradling for these.
I have a tempera that is 14" x 42" and it, when held in center, wants to have about an inch warp, but it takes just a wisp of effort to straighten it. The simple act of fitting it in a frame will suffice for that size. In other words, the light warp that exists is not a rigid warp if you take my meaning.(?)
So this is my direction, no cradle, but one can be fitted in the future if something occurs. there are a couple options.
I will not pretend to be any kind of seasoned expert in the large painting category.
Most of my work is small, which is the result of drawing in school in notation margins. These are hyooj undertakings for someone like me.