It is hit and miss, but before considering breeding your splash overo, you may want to test for frame to eliminate the possibilities of producing a lethal white. It hides itself quite well, and your mare may be a carrier -to me, she looks more like a minimally expressed frame than she does a splash IMO. If your mare is a carrier, any stallion that is also a carrier should be removed off your list. From there you can look at other studs with the splash gene, but it is going to be a gamble to get what you are looking for. It may be far easier to find a young foal on the market that has the color, conformation, and breeding that you desire.
I know that in my mom's case, she wasn't able to find what she was looking for on the horse market, so she is breeding for it. She is guaranteed the color she wants but not the gender or markings that she desires. She made selective choices in mare and stallion that increases her odds of getting what she wants with breeding well conformed, well bred, and good temperaments that carry the traits to produce the coloration she is trying to acheive.
Edit- ND replied before me, I take forever to type and proof read