From your spelling I cant figure out if you want to level the cross hairs of your rectal or your reticle, either way I can help you out.
If it is your rectal cross hairs you want to level it is very simple. take a bubble level and put it on your toilet seat and slip in a sheet of TP or 2 in one of the four corners until the bubble is in the center (centre if you are french). then sit and measure the distance between your hips and knees, when the distance is the same your rectal crosshairs are level.
If it is your reticle cross hairs you are trying to level $18.50 to Sinclair for a Segway reticle leveler is a bargain. mine was made by 7mmrhb that slides into your action so it is perfectly square to the bore of your barrel because it sits on your bolt lug recesses.
UB
ps If you are trying to eyeball it the reticle is 99.9% better than the rectal