Glad you got-r-done! Its probably too late now (you already painted it) but, here are some pics of the rear mounts I was talking about. The first photo shows the rear end of the THORparts front bumper. There are (4) additional fasteners at the rear that keep the bumper from "rotating" under load. ARB, BA, DOI, etc...all have similar rear attachment points. The second photo shows the factory frame brackets that they bolt to (shown with a cardboard mock-up bumper). They seem rather flemsy by themselves but, once you bolt-up both sides...the entire bumper assembly becomes much stronger. These brackets are already on your H3, and I would never run a winch bumper without utilizing them.
Without these additional attachment points, your bumper may tend to "rotate" and possibly bend the frame rails...
especially if you are winching at extreme up or down angles. In the case of your bumper, the problem would be amplified because the outer ends would rotate upward with it, and possibly rise up enough to contact or crack the plastic grille. This is the same issue that add-on shelf type winch mounts have, which also have no rear attachment points. This basic problem is that the frame plates are on the same vertical plane, which does nothing to combat the rotational load. To help prevent this, some guys running shelf type winch mounts, weld-on thicker end plates. It helps the end plates but, does not address the frame rails. The frame rails are designed to bend in an impact, and they bend quite easily. Adding some rear mounts to the bumper will do wonders to prevent this, and it only requires welding on the bumper (and not welding on the truck). Posers don't bother...the bumper will be fine as-is. But, if you plan to do some winching...I would get it bolted down better.
Other comments...
1. If you do weld on your truck...disconnect the battery.
2. Hate the "MOVE" logo...I would order mine without (or fill it in).
3. Hate the visible welds. Five minutes with a grinder...then chase them with a flapper wheel...will make the bumper look like its all one seamless piece.
4. Grab a piece of cardboard and mock-up your custom front skid...you can take your cardboard and get it cut & formed at any sheet metal shop.
5. You probably didn't notice any drop in the nose...but you will when you add your winch. A simple twist of the t-bars will cure that.
6. After you mount the winch...go find a sturdy tree limb...park directly below it...and slowly winch your front wheels off the ground. Check the bumper for any movement...STOP if you see it starting to rotate.
Overall...nice looking job. Can't complain too much considering the price. Maybe just needs a few tweeks to strengthen it.