Help with plan Size
I go along with what CoosBay recomended but with a little twist.
If you can find some plan that's close to what you want then just use one of the free CAD programs to scale it to the right size without bothering with the wood size changes. If it's within 20% of the size you want anyway then the sizes will probably be fine. For blocks and the like you'll have to just use a ruler (gasp) and measure off the plan.
If it's a 3/4 reduction then it's easy to just use the next smaller size than what they call for in each case.
Use the scaling option in the CAD program to scale to the right size and then take the file to somwhere with a plotter for the printout. I gather Kinko's can do the photocopy thing. Cnances are they also can handle the computer DXF or DWG file as well. I'm in Canada so I dont' know but a phone call will soon answer that.