I had the best luck when I turned the buggy upside down to get the straps really tight.
US40
HQ 1.4m which my 8 and 10 year old fly
Pansh Flux 2m, Legend 3m,
HQ Hydra 300 PZ depower, Neo 8m, 11m
Flysurfer S3 Deluxe 19m, S2 15m
Flexboardz Haize
Radbuggy
SIMS snowboard
Crazy Fly 145