Martha, we've never had a Welsh, but we've had terriers. Weatherby was a Jack Russell & Ronnie's family had Scotties when he lived with them. We just looked at different breeds & did eliminations according to what we wanted & didn't want. I wanted one that didn't shed a lot, I'm still finding Weatherby's white hairs on stuff.
I wanted one that was small enough that I could easily pick up, like I had to do twice in campgrounds when big dogs were running free & came after him. Ronnie didn't want a dog that was too small or too "girly".
and we wanted one that had personality, like the terriers do. Then we just looked at the breeds that were left & decided.