My current location is to break the jack down and stuff the foot plate, handle, ladder beam and top piece into the front crossmember. I use the foot plate and the top peice to lock it all into place. It doesn't rattle.
Althought once it's put together it goes either on ym roof rack or in the back. I've got to make a hard mount for it.
Other options, would be across the floor behind the driver seat. Use U-bolts to the roll cage and secure the jack behind the rear seat.
If you ahve a dual tube bumper then you can use brackets and large bolts to clamp the jack between the tubes.
or else but a Hi-lift mount. There are many options. I'm not a fan of the hood or engine compartment mounts.