It looks like E6 parts are a bit harder to find than E7 parts. As long as you are cutting to appropriate length, either E6 or E7 parts should work, but longer E7 parts may be $1 to $2 more expensive per part.
1) E6 Boom (
part 615-140) -- I cut mine from the original 770mm down to 700mm.
2) E7 boom supports (
part 315-117) -- I cut mine down to 500mm.
3) E6 TT (
part 320-501) -- I cut mine from the original 760mm down to 689mm.
4) E7 Tail control rod (
part 315-111) -- cut to length
5) Consider the 4.5:1 tail gear ratio (54T Spur Gear part 320-154 and 12T Spur Gear part 320-112)