to add to what BG said bottomed out refers to the limbs being at the lowest point in the riser pocket which is against the riser inside the pocket which as BG and i have said will give you max draw weight.
Also once you get your bow maxed out and tiller set its time to go to the pro shop to find out what the draw weight and draw length of the bow is, and decide on what grainbroadhead you want to use then use a chart to find the proper spine for your arrow length and draw weight which is easier than getting the arrow in the length and spine then trying to work in the broadhead.
http://www.huntersfriend.com/bowselection.htmthere is a tech help section which will guide you in arrow selection too