Tony and All,
The "Unofficial HOTSPOT Instructions" are indeed written by Bob Wilcox. I followed them, along with the Grauper instructions, on mine- with some minor mods.
I chose to mount the elevon servos with the linkages existing the top of the wing- saves gears and linkages on a gear-up landing. I also buried thin-wing servos in the fins with direct linkage to the rudders- use a JR Matchbox or equiv. to link the rudders and nose gear steering. My landing gear is from Robart, specifically made for the HS with Trim wheels and brakes. Be sure to get your gear for the HS to provide the correct ground stance for proper takeoffs and landings- the Kangeroo/Rookie gear is too short. Also, build wheel wells to prevent the air stream from entering the wing cavity and ripping off the lower, rear sheeting-which is fatal to the airframe. Finally, adjust the elevons for reflex as stated in Bob's instructions- the newer wing sections have the reflex designed in and no up trim is required. His recommended CG is correct but you can vary itto suit your flying style.
Good luck with this vintage jet.

Art ARRO, Sr. Jet Pilot