You can use the "simple" one for that:
https://www.directadmin.com/install.php
No, 250Mb is too low for /boot today. It would be better to have 500Mb for /boot. And 12Gb for swap imho is a waste of the disk space. If your system utilizes even a half of 12Gb of swap hardly it will be any longer usable, you most likely will need to reboot your server due to too high server load.