Those Hi-Lifts are great, but they've caused collective damage in the millions to various rigs. The problem is they can kick out. If it's towards the rig, it can all but act like a can opener.

What you REALLY want is an X-Jack. http://www.bushranger.com.au/xjack.php Not only more stable, but it'll lift about as high. (30") And, they're great on soft stuff, where a Hi-Lift needs a large pad to keep from sinking in.