@JD300, see if you can find a level where ± 1° can be clearly identified as a minimum. 1° of unwanted cant will give 175mm of unintended windage offset for 10 metres of elevation correction, which is a typical enough figure for shooting at 1km, and where that size of offset corresponds to 0.6moa.
Nice thanks for the info any brands you might suggest as good to use ?
I'll ask questions of the suppliers to find out the accuracy in the future.