heres the Nar records
https://www.nar.org/NARrecords.shtml
you can build an altitude contender by just following the guidelines in Stine's handbook..10 to 1 ratio, delta or clipped delta fins ,minimum diameter, tower launch, long burn motors, eliptical nosecones, airfoiling, super slick finish,finding the ideal mass,,,
you can also look at sounding rocket designs for ideas.