I built a Tri-Star. I really like that kit. building it was very enjoyable because the tubes easily glue straight and the fins go right on and straight. I liked flying it on 3xF20-7s best.
on its last flight (3xG35-7s), the shock cord separated - the nose cone, upper tube, and reducer flew away, and the body tube crashed.
so, because of the 3 ejection charges, use a LOT of wadding and dog barf. also, consider upgrading the LOC "underwear elastic" shock cord to tubular nylon or even kevlar. last, consider taking the powder charge out of one of the motors - 2 is more than enough.
I have a 3" coupler and length of airframe and nose cone - the Tri-Star shall rise again but somewhat different ...
I used FireFly igniters. they always light all three motors.
there is a thread about building one
here
but I guess that's the same as the EMRR review.