I owned Zen's 1P29 before I sold it to him. I also own the Zeiss ZFK 4x25 optic which is also calibrated for the AK74. I wanted a true AK74 optic but somehow ended up with two - yes, two of the most sought after and rare AK74 optics because they were military (not hunting) versions of optics no longer in production. These are sought by people who want an authentic and legitimate mate to their beloved AK74. I liked the Zeiss style better so I kept that one, and knowing TX-Zen's desire to dominate the authentic AK74 marketplace - I teased him into buying the 1P29. He was the right person for it, and I gave it to him for what it cost me. It was the perfect match, and the 1P29 had found it's proper home.
I had acquired both manuals for the optics - therefore I had the information necessary to adjust the clamp pressure to assure optimal fit to the AK's scope rail. Having those manuals mated with the scope kits make the entire package as complete as possible. If you're going to spend the money and get something made in Russia or East Germany, then you should have the manual(s) to fully appreciate and properly use.
I don't know for sure about your PO3.5x - but in my limited experience of owning two military grade AK-74 optics, there was an engineered way to adjust the clamp pressure - and with a properly adjusted clamp the optic will perform as desired (won't move from it's mount).
The trick is to find out the correct method before bending or breaking the mount. Russian engineering can be odd, and with the information you can make the adjustment successfully - but frankly, without the information (manual) it can be very difficult to figure it out.
So, to make a long story short - be careful and find out how these clamps are designed to adjust pressure. It's worth doing right, and too easy to damage a unit by doing it wrong.
The exploded diagram is often enough - but realize the manuals may be written in Russian or another language. There are some versions out there that are translated - some well, some pretty raw.
Hopefully the adjustment you need is in the clamp, and not the mount itself. As far as I know, there is no adjustment for the mount - it's either properly riveted or not. On my SGL31-94, the mount is well attached and not moving even a little.