HI J, Yea, standing free-hand is a way different animal than benched................'Have noted your skills & patience in refurbing these great rifles. You make them " some kind of wonderful"..........
The front sight circular inserts combined with the Diopter rear along with the proper 10 meter target, your eye naturally aligns everything up. Once YOU get into the groove that is.
Back to the subject of sights, it is a great help to use an adjustable-opening iris for the rear sight. This will help to always get the best focus depth-of-field possible with whatever light you have (the target disks supplied with most guns have an opening around 1.0 mm in diameter, which has the additional advantage of a "lens" effect that sharpens the sight picture, but you need good bright lighting to use such a small opening effectively). The Gehmann 510 is a good example:https://gehmann.com/en/510-Gehmann-rearsight-iris/GEH100132Iris units can be had with a 1.5x, magnifying/focusing lens which is a nice step up. These are understandably illegal for most formal matches (!), but a terrific aid for older eyes. Irises can also have colored filters and polarizing filters which are useful in some situations. You can get these add-on goodies in any combination of 2, 3, or all 4, but at significant extra cost of course! The Gehmann 575 is such a "kitchen sink" model, LOL:https://gehmann.com/en/575-Gehmann-iris-6-colour-twin-polariser-1.5x-lens/GEH101242BUT - the basic adjustable iris is the most important element by far, and those aren't too expensive. The "eagle eye" is a similar, fixed-focus lens for the front sight. Those can help too, but I find the rear sight gadgets vastly more important.