I'm in need of some assistance.

Currently I am 5000 km away from my boat "Celtic Kiss" and am designing some modifications from afar. The CL16 comes with only one design flaw that I'm aware of.
The spreaders sag because they are not butted properly to the brackets they hang from. I don't know if this affects mast support in heavy air. I have been informed that this "flaw" can be jury-rigged by adding wooden dowels to the spreaders, but I want to do more. I want to make new spreaders. After some diligent thinking, I chose to use 1/2" copper tubing. The ends of the tubing have been pinched to fit inside the brackets. (The new brackets are made stonger than the older type so I'm not concerned about metal fatigue) This was done with a pair of pliers and did not require a lot of strength as copper is fairly malleable and strength is not sacrificed. (I was also informed by the staff at Home Depot that copper will harden with age) " So many witty responses I can't pick"

I chose copper tubing over wood dowels because copper is strong,light and,will not splinter in a high wind and the shock of pounding waves. (I love the heavy stuff around 25-30+ knots).

What I need to know is, what is the measurement from the inside of the mast-bracket to the shroud (sidestay) when rigged?

I am currently sanding the tubes to roughen the finish, so the spray-paint will adhere to them. After they are cut to length I have to figure out a way to cut a slit for the shrouds to slide into the spreader . I think that carefully drilled holes side-by-side and a bit of filing will do the trick.

Your help is most definitely appreciated.

Thanks so much, that is precisely the info I need.