i really disagree w/ setting axle to axle equal on both sides of the bow at rest. i really disagree with it.(unless you've got a shoot thru cable system). while you can do a worse job setting your bow up than this, it would be tough. while mathews is giving you tricks to do w/ arrows and such - they're not telling you why. what you're trying to do w/ the idler is decrease horizontal nock travel on the one thing besides your rest that you can. if you set the bow up parallel at rest, your string will have the most amount of left to right movement (or right to left) throughout the shot that it can possibly have - unless you really screw things up.you shouldn't set it it perfect at full draw either - because you're on the other end of thedeal then.w/out tools and lasers - what you can do is set the bows ata perfect on both sides at rest - and thencount the twists/untwists to one side of the yoke necessary to acheive the string coming off the bows idler perfectly straight at full draw - and then split the difference. so if you had it perfect at rest, and you had to take 6 twists out of the right side of the yoke to get it perfect at full draw - then put 3 back in - this way your string has its least amount of horizontal nock travel across a center line possible. this is, as far as the idler goes, your bows most forgiving point. i wouldn't suggest drawing a single cam bow that's set perfect axle to axle on both sides, as sometimes the cable won't track properly on shorter ata bows, and the serving can get cut.