Horseman 970 infinity stops-correctly positioned?

I'm a longtime MF camera fan, but I'm new to Horseman technical and field cameras. I've also used view cameras, but my question here is peculiar to field and press cameras: I have a 105mm lens mounted, and there are the usual array of infinity stops on the camera's rails, each with the traces of a distinguishing color which is supposed to match the correct Horseman cam and Horseman lens. Right. Everything seems right, although there are two different pairs of stops using the same color as the cam and the lens (and I've tried both pair, with the same results) Anyway, regardless which pair of stops I set the front standards at, the lens won't focus. So is there an efficient way of re-setting the infinity stops, even if it boils down to measuring the distance in mm from the film plane to...where, exactly? and moving the stops accordingly? Finding the film plane is no problem. Putting the lens in the right spot is a different story.

I don't know Horseman cameras at all, but my Century Graphic depends on infinity stops. Each one screws down on the rail with two little screws,and they fold down out of the way, so you can have several pairs on the camera, and just fold up the ones for the lens you're using.

I set the infinity stops by putting the lens at infinity focus, and sliding the stops up against the lens carriage to match. Fisrt I set the camera up to look at a scene with some decent detail 'at infinity'; an antenna or chimney anywhere beyond 100 metres away is fine. I make sure the focus rails are racked right back; when I first unfold the camera, it tends to be a little way forward, so I have to rack it back to infinity. I loosen the pair of stops I'm adjusting, and slide them forward out of the way. Then I slide the lens carriage out to about where I expect infinity focus to be. I sort of half-tighten the locking lever of the carriage, so I can slide the carriage forward or back with my thumbs, but only by a deliberate movement. Then I simply do that, while looking at the ground glass with a loupe. When I've got decent focus at infinity, I look closely at the rails on each side, and measure to see that the carriage is at the same distance forward on each rail; adjust it if not, and re-check the focus on the screen. When I've got a good infinity focus on the ground glass, with the lens carriage at right-angles to the rails, I slide the stops back against the carriage, and screw them down. The final check is to fold the camera up, then unfold it and pull the lens out to those stops, and see if it's right.

Dustin's advise is spot on, but a trick that helps is to use the full moon at night for a focus target... truly infinity and easy to focus on with a loupe.