That depends on the mast.
I use a 10m DX Wire Mini mast and a 6m Decathlon mast. The Decathlon mast stands securely in the holder.
The 10m mast is either leaned against it somewhere, fixed with elastic Velcro or, if necessary, braced with a ring disk with holes.
My endfed has a few meters of rope at the end. I tie it to something (branch, tuft of grass,…) and if necessary I also have a tent nail with me to tighten the antenna wire.
The space always determines the structure (Inv. L, Inv. V,…) I usually sit next to the mast and the coax feed is at the foot of the mast. From there the coax goes to the place where I can sit comfortably.
If you run the cable loosely on the mast, you can vary everything easily…
73 Armin