you should be ok with what you have, but if you can id pull it during tillering with a string from back a bit just to be safe. you shouldnt be disapointed in it if it makes it, one of my very favorite bows is a red oak longbow, full 6' long, very sweet shooting, accurate, and feels very light in the hand for its length. i do the majority of my red oak bows from the basic design on sam harpers site, although i change the dimensions of the tapers from bow to bow depending on the length. ideally i leave the limbs full width out to about an inch or two past midlimb, then taper to 1/2" or less nocks from there. since red oak isnt great in compression i think this really helps give it more working inner and midlimb to keep set at a minimum, and so far i havent had a single bow that disapointed. pyramid layouts are great for true 2" and wider boards, because they have enough wood to take the stress close to the fades, allowing set to localize there instead of over the entire limb. not saying you cant build a more narrow pyramid, as a matter of fact im working on a laminate pyramid red oak right now as an experiment in some techniques. 12" is fairly long for a riser joel, ive never done one longer than 10", and after that one i started using 8"riser/handle sections. ideally you want to retain more working limb, at the same time giving yourself just enough strength at center to provide for cut in shelves. with a 12" riser you would be looking at about 3 inch fades and a 6 inch handle,or 2 inch fades and an 8 inch handle. really you can go as small as 1 3/4" to 2" fades. when i do a riser or handle glued on i use every part of that riser for a specific purpose, so i can make smaller handles, for example, the bottom half of a 4" handle and the fade attached to it becomes the section of the handle which rests in my palm, and the top half has the shelf shaped in, with a dish between the two for a locator. all the curves are smoothed out and eventually blend into the fades. not trying to preach but i thought it might help elaborate on how i see the mix between form and function for handles and explain what you can do with them.