Strings - brands and gauges?

So my used dulcimer came with strings as follow: 0.020", 0.010", 0.010" and 0.010"

The strings are rusty and I should probably buy a couple of sets to keep on hand. I expect when I break one I will swap the whole rusty set out for new.

What brands and sizes should I consider? I have not found 20/10/10/10 yet. I have found 22/14/12/12 and 24/13/11/11.

I am leaning towards DAA tuning based on advice I am getting.