print 2 parts out. get some Para Cord just a little longer than your old straps.
strip out the inside of the ParaCord.
feed it in the Eye of a Zip tie. (what i used) or print one out. cut off the zip tie tail. to make the tightener.
now the hard part use some tape and off set the Para cord and feed it in the Printed part use a small flat blade screwdriver or something if needed.
get it in and the line it up and to the right length.
glue and melt the ends of the ParaCord and pull it in to the printed part clean off the ends with sandpaper if needed.