If you are going to use those things to hold up your mast, then I would at the very least, use the correct size. Too small and you may damage the wire; too large and they won't be secure.
Of course, as mentioned above, there are better alternatives and since it's something one does not replace very often, it might be wise to consider them, instead of "jury rigging" your rigging.
Spider, I'm with these folks above... those things are for temporary fixes only in emergency... again assuming you are talking shrouds/stays... They should be properly swaged, and sized for the boat.
Riggers earn their money for sure... sizing this stuff perfectly is a bear, but since it really only needs done every 5-10 years... best to do it right. The cost of doing it wrong is more than just the price of a mast. While a suppose dismasting is a real possibility no matter what you do, I'd always feel better giving it my best effort to avoid it, and nearly all costs.
The reason I am replacing the stays is because the current wire is 1x7 and has kinks in it where the previous owner pinched it, also I am upgrading from 1/8" because I was worried the 1x7 1/8" might break after enough time if I use a trapeze.
Also they are 5/32", do you think the smaller 1/8" tool would work or do I have to get the bigger one.
Yea I was going to buy 1/8 to replace the 1/8 on there but some listed the working load as 400 lb or so, I was worried that with my weight on the mast too from a trapeze, that a line might become over stressed. Figured they put the right line on there for the sails, but not the sails plus me.
What is the point of working load limit rating then?
Load Limit Definitions
The Working Load Limit is the maximum load which should ever be applied to the product, even when the product is new and when the load is uniformly applied - straight line pull only. Avoid side loading. All catalog ratings are based upon usual environmental conditions and consideration must be given to unusual conditions such as extreme high or low temperatures, chemical solutions or vapors, prolonged immersion in salt water, etc. Never exceed the Working Load Limit.
That is what I am going off of and 1/8" was 400 lbs.
I figured the force of the wind on the sails and my 200 lbs hanging off the side would be greater than 400 lbs of force.