I bore sight by looking down the bore at a Target on my wall at about 25'. I have a mark on the target about 2" high. (I have never measured it......I made the mark with a rifle that was already sighted in.) I find with most guns, if the bore is centered on the bull, the cross hairs should be on the mark 2" above the bull......This has never failed to get my on paper at 100 yards. I would assume the laser would be the same concept......Also many people have issues when bore sighting because you have to tweak your thinking on what way to move the reticule.......If your cross hair is above the target when bore sighting, realize that you will be hitting low, because you will lower the barrel to get on target. So to move the reticle DOWN towards the target, you have to click the scope UP....... If you center the bore with the crosshair at close range, you will be shooting way high due to the different planes of view and bore.
I only Have one rifle that I couldn't zero at 100 yards with a 20MOA base......My thoughts are it probably closer to a 25 or 30 base, So I think you should be able to get it zero'd with the base you have. Hope this helps!