Well as already mentioned just modify grub.cfg.Another alternative would be chainloading the iso. This way it wouldn't even be modified while being able to customize menus.
It depends on the purpose and the process which way to go.Personally I always found especially the mini.iso useful as is excluding environments with uboot where prebuilt images are the preferred way . Also I prefer the daily builds to not run into dependency issues where no matching kernel can be found in the repo.
