If you can get by,with makeing your own.Do it.Good luck.Later
down the road you can always upgrade.What
I did for A harness.Go buy some 1.5 to 2 inch nylon straps.The tie down kind are perfect.Buy A $10.00 rivet gun.
Make your own.You can make it addjustable.With A rivet gun and
A sewing machine.Your good to go.If you get lucky.When you
buy the nylon straps they'll have the connectors.(black snap
connectors)Use those as well.My harnss has the female ends mounted to them.Leave straps on the top of your jet pack.
Mount the male ends there.So inessance your feeding the straps from your jet pack thru Your backplate and vest.Attach them to the female alreay mounted to your harness.As for the bottom of your jet pack.Two straps attached to the jet pack.Left side female right side male.
Same as before Feed thru the backplate and vest.Instead of attaching to your harness.Attach them to each other.This is very stable.I can jump up and down.My pack does not move.This all makes since in my world.I hope you can follow this and it helps.good Luck