Hello, I live in Washington state as well. I have a toro 30" and love it on certain properties. But the 21" is used more often. I wish I would have bought a YBravo 25". You should check those out if you are in the market. Also, if you are push mowing mostly, I'd use those platforms they sell for mobility scooters etc that go in receiver hitch----you can drive a pusher right on them and you wont need a trailer. I have one called "tilt-a-rack". and its awesome if I'm only doing push mow jobs that day. Having a flatbed truck is a huge + as well.
I had a couple small wright standers. Ended up selling them because were kinda heavy for the qualifying residentials and were too small for the bigger jobs. plus could get same work done with the 30". Now I run an exmark 52" vantage a 52" lazer z. plus honda 21" and the toro 30" and they all fit on my 7x10 single axle trailer at once.
Took me a long time to figure out what equipment best suits my needs. Hope this helps and good luck!