Gregg,Yes ... any degree rake kit will fit; however, this question should really be directed to the manufacture of the trike kit itself. Notice that I did not say to ask the installing dealer. The best rake degree for most kits can also be found on the manufactures web page.
Here is what I find to be true. Many installers will charge you for a "branded" rake kit, but instead they'll install a non-branded or aftermarket kit. The aftermarket kits sell for about 1/2 the price and often only come in 1 generic angle 6.5 deg. These aftermarket kits may not be at all in the customers best interest. However, for the installer, it is much better mark-up.
My advise, insist on the kit your trike manufactures says to use and accept nothing else.
How can I tell if my 5.5* front end is what my dealer claims it is?? (thanks for the suggestion)