Probably done to death but each is a little different i suppose.....
First, the basic mount.
Formed from cut and welded 5mm steel picking up on the existing 6 chassis nuts.
Usually i use 6mm but i didn't have any, besides which this is a leisure vehicle. If i was intending to pull every weekend with it then i would have gone for 6mm and faffed about cutting the welded nuts out and replacing them with a reinforcement plate. As it is this isn't a commercial recovery vehicle thats going to go a year without having it's winch mount checked.....

Here you can see some of the underside reinforcement, basically the winch mounting holes are no further than 25mm from a reinforcing angle.
This isn't any manufacturers guideline but based on engineering experience of what works and is/isn't needed

Winch fitted, in this case a commissioned "prime-tech" 12,000lb from Germany (China) Nothing spectacular to report, it drags like a typical brake in drum, motor looks ok, took a while to bed the brushes in though.
Wiring leads to a Durite contactor mounted on the battery, wired to a loadsure remote control, simply because i had both laying about.....

Fortunately I can reach the freewheel through the vent hole in the bumper

Sliders next, before i lose these standard steps............
First, the basic mount.
Formed from cut and welded 5mm steel picking up on the existing 6 chassis nuts.
Usually i use 6mm but i didn't have any, besides which this is a leisure vehicle. If i was intending to pull every weekend with it then i would have gone for 6mm and faffed about cutting the welded nuts out and replacing them with a reinforcement plate. As it is this isn't a commercial recovery vehicle thats going to go a year without having it's winch mount checked.....

Here you can see some of the underside reinforcement, basically the winch mounting holes are no further than 25mm from a reinforcing angle.
This isn't any manufacturers guideline but based on engineering experience of what works and is/isn't needed

Winch fitted, in this case a commissioned "prime-tech" 12,000lb from Germany (China) Nothing spectacular to report, it drags like a typical brake in drum, motor looks ok, took a while to bed the brushes in though.
Wiring leads to a Durite contactor mounted on the battery, wired to a loadsure remote control, simply because i had both laying about.....

Fortunately I can reach the freewheel through the vent hole in the bumper

Sliders next, before i lose these standard steps............