I understand your layout, now, and believe the best course of action, as you suggested, is to buy new spreader end caps and re-rig your mast
. It will be a cleaner, simpler installation
without the superfluous turnbuckles that require occasional tweaking/maintenance. There is also the concern for rig failure due to cracking of the terminal piece to which the stays/shrouds attach. All boats have design flaws and/or poor designs that can be modified to become simpler. I think this installation
is a good example of that principle. Good luck and good sailing.