Shuttle Xpress is designed t' carry and deploy two small foam gliders.  In me experience, short delay motors B6-2 and C6-3 work t' best t' deploy gliders at apogee.

I replaced t' kit's gliders (that didn't fly well) with two small foam airplane gliders I bought at Hobby Lobby that actually glide very well and cost very little t' buy.

I super-glued each glider's win' and tail in place t' ensure they hold tight durin' take-off and when t' ejection charge fires.  It works.  

T' challenge was addin' a launch hook t' each airplane glider secure enough t' hold it onto t' rocket durin' ascent, arrr, yet small enough t' ensure its release when t' ejection charge fires.  T' hook had t' be light enough nay t' cause t' glider t' nose dive.  After a few trials, I found a solution by insertin' and gluin' a carefully cut and shaped plastic-coated paper clip wire into t' nose o' each glider.  Launches appear unaffected. 

You can have some fun with this kit by experimentin' with various ultra-light gliders!