How to connect two pieces of chain?
Max, I don''t have a specific suggestion re: HT shackles. I bought some a few years ago from a firm up in RI as I recall; Google should get you what you need. If you find a source, it would be helpful to post the vendor''s name here. Why large retailers like WM (or Defender, or Sailnet) don''t carry these items when they sell HT chain is beyond me...
The normal method for building up a chain to rope splice involves protecting the splice thoroughly after it''s in place. To me, this suggests than any chain to chain splice will be cumbersome and short-lived. A Mid-Link is a much better, safer option. If your two shots of chain are different lengths, place the Mid-Link where it is least likely to see the windlass gypsey.