@Luvdog: Thanks for the calculator. Confirms my calculations. Would have spared me some minutes of math. On the other hand, I like doing the simple stuff...

I also directly contacted the CZ support and received following answer:
The distance between the barrel and the lower edge of the Picatinny rail is 3.39 mm and the distance between the barrel and the mounting groove of the rail is 8.49 mm. With this in mind, a 1" mount should be sufficent.
Hope this answer was for You helpful.
So my measurement based on an image to the height confirmed by the manufacturer only differs 0.51 mm.
After this official confirmation, I went crazy and simply bought Spuhr SR-4000 Rings (1" height).
All in all, I paid nearly twice the price for the scope and mounting rings compared to the CZ 457 LRP rifle. From what I've seen on Youtube, this rifle doesn't deserve any less. Waiting like a child for the deliveries

Thank all of you guys for the support and I wish you all the best! Stay healthy
