well, when making the bracket to mount the shocks, you can basically design your our ride height. do this by either putting a jack under the frame at the front or by using a block and tackle and winch it up from a roof beam or something. Take the wheels off, Now jack up the frame and measure from a set point on the frame to the ground (best take off the bumper and use the front end of the frame) jack up the bike until you find the height you are looking for. I suggest you measure another bike to get an idea of what the height should be. I used a yfz 450 to get my ride height.
Once you have it jacked at the right height, put the shocks in on the bottom mount only. then position the shock to the point were you feel they should be. Be careful here tho, you need the shock at the right angle or else they will loose their efficiency at absorbing bumps.
What I did was measure the distance apart of the stock blaster top shock mounts (200mm in 1st pic) then I measured the same thing on the YFZ, it was 300mm. Then because of my frame being wider than a YFZ and my overal width was going to be 17mm wider than the YFZ, I had to add 8.5mm on each side of the YFZ's measurement of 300mm making it 317mm. This then kept the proportions and geometry of the 450 and transferred it to the blaster thus putting the shock at the same angle.
So now I knew how wide apart my top mount should be (X axis) but I still needed the height (Y axis) this is where the jacking the frame story comes in. I matched my ground clearance with the 450 and that resulted in the mounting points being a little lower than the stock blaster ones, as in the pic, so along the 317mm line I held the shock and set the ground clearance. Then make left and right the same.
Its hard to explain. Takes a bit of logic when doing.
In your case, Id suggest getting a ground clearance value off another bike, or set it where you feel it looks right then add +3 to the 200mm of the blaster shock mount width (are your arms +3 inches on each side??)
Another method, because like you say you are not using 450 arms, is to measure the angle of the shock on a 450 in relation to the horizontal plane and apply the same angle to your bike. You can use a carpenters sliding bevel to do this.
I suggest reas through my report on what I did in the suspension section (sticky) and that should help you getn an idea of the logic you need to apply. I didnt go into too much detail with this there but i may have mentioned something else I have since forgotton!