please show us the checks
sinew bow usually fair will in dry climate,,
maybe the bow was over stressed before the sinew was appied??
I did blow up a bow a few days ago,, and am sure RH was a factor ,, but other factors were
over stressing the design
too thin on the sinew layer,,
really just not enough wood for the weight I was pulling, or the draw length,,
but the bow did not have any chrysals,, and I have not had a problem with that,
I did have a friend that chrysaled his bow ,,when first bracing and had a weak spot,,that caused the problem,,
it is really dry here in Santa Fe, New Mexico,,
I guess my point is, other factors may be an issue as well as the RH,, you should be able to get a good stable sinew bow,,