Two quick comments here: One needs to be very careful in designing with the Graphlite rods since it is tempting to use the design/strength values as published. The problem with this though is that those properties are as tested in a laboratory setting. Now don't get me wrong, Graphlite rods are great but if you're really expecting over 300ksi in strength you might be surprised. First off, many folks tend to use the round rods rather than the rectangular ones, but then calculate their spar as a solid rather than a matrix with a bunch of voids. This of course reduces the effective working area and so is not a proper representation of the structure. Furthermore, there is a big difference often times between the lab specimen and the behavior of the high strength elements in actual application, especially in compression. And that of course might be further exaserbatd when discussing structures built in a typical "homebuilt" environment. For that reason it is very advisable to be substantially more conservative in the design of these type of multi-element spars in order to account for all the less than ideal variables. Regarding the use of Nomex honeycomb in homebuilts, the lack of application is generally due tot he material's characteristics. Structurally it's excellent however incorporating it in the structure in a sound and efficient way pretty much requires the use of prepregs and oven cures. Folks that have tried to use it within the homebuilt field using wet layup techniques were often disappointed with the result. The most common problems are an insufficient bond and an overweight structure (the latter from having the resin fill up the honeycomb voids).