I've noted a number of threads where folks get replacements from HH or made by strapworks ... that's cool and safe and appropriate.
Here in the PNW and specifically the Olympic National Park we've got lots of big tree species size records ... true woppers all around and cathederal-like places.... but watch out for the moss.
I make our custom length huggers with a thread color code for length determination. Most decent sewing machines will do a good job.... the newer Janome machines (eg) have a ZZ stitch which is virtually identical to Hennessy's hugger stitch ... which I exceed in quality BTW.
Sewing your own is not to be taken lightly cuz ya gotta do it right or else
Thread seal with diluted Shoe Goo © like with trout, steelhead and salmon flies.