Recipe for pH meter storage solution?

I believe I read that storage solution is distilled water and potassium chloride.

Salt substitute is KCl, fumaric acid, Ca3(PO4)2, and Ca(H2PO4)2.

Do the Ca phosphates and fumaric acid in salt substitute ruin it for storage solution or can it be used. If so, at what water/salt ratio?

I can't speak for the reference electrolyte of your exact model (check your meter's manual), but a 3 mol/L KCl solution is pretty common. That's 224 grams of (pure) KCl per liter of distilled if you want make your own.

Others will know more about the other solutions, I've never used them.

Some manufacturers (e.g. Cole Parmer) recommend a 3 M solution of KCL, others (e.g. Hach) recommend a saturated (4 M) solution and presumably others recommend other strengths. Some manufacturers have you store in one or the other of the buffers. It is best to follow the manufacturer's recommendation.

As KCl is easy to obtain I would, first, find out what your manufacturer recommends and then go to a lab supply house to obtain ACS grade KCl and use that to make up whatever strength your manufacturer recommends. It is probably much simpler and probably not that more expesive to by the manufacturer's pre-mixed storage solution.