I use digital calipers to check my thickness and widths on my levers...my standard measurements are .750" at the beginning of the levers... .500" 6" from the nocks...and .300" at the string groove...now I have gone less than that when the wood and bow allows me too... narrowest at the groves I've gone is .243" ..sorry I'm a machinist and speak in decimals and thousands of an inch ... as with any wood bow the thickness is going to vary and never be the same from one bow to the other..but start out with plenty of thickness and width for string tracking adjustments if needed...just leave the thickness alone till you hit full draw and right before you would start shooting the bow...this is when I reduce my levers down...because you won't know how thin the thinnest part of your working limbs will be...I first reduce my width to the standard set of numbers given...and I start out reducing my thickness .200" thicker than the thinnest part of my working limb(which is always at the end of the working limb right before the lever fade area on a well tillered bow)...and that is just a starting point...then its trial and error reducing them wee bits at a time making sure everything is still stable..you want to reduce them down to where right before they start to flex or just barely flex(pending on what the wood tells ya it can be that narrow n flex or not) ...you should barely be able to discern whether or not its slightly flexing or not...its the most critical part of making a lever bow,so at this point go slow and be patient...