Does anyone have a recommendation on the best Miticide / Acaricide to start with in Oregon?

FOr what?

I would just go to a good garden centre and ask them what they stock against the specific pest you have. No need for bonsai-stuff.

Spider mites.

DoYourOwn recommended Avid because it has a long residual. Someone in another forum recommended a “group 21” but hasn’t come back to give any specific recommendations and I can’t find any group 21 acaricides I’ve ever heard of.

Other options were Forbid4F and Sultan. People seem to like those.

The stuff is so expensive I really don’t want to “buy to try”. Was hoping for a solid recommendation on something specific.

My experience is that sometimes the first thing I try works and sometimes the second thing. Sometimes the third. Try the least invasive and most natural thing first, like spraying with water. Proceed to spraying with a soap mixture as many have recommended. Try neem oil.

Go to the pesticide section at the local big box hardware store. Try systemic powders. One day the plants will look great, so remember what the last thing used was.

For spider mites i use Phytoseiulus persimilis. Works every time.

I use the water jet (Mirai has a good video about it) every day for 12 days.
If I still see signs of spider mites after this period, then I use a spraying mix of 90% water, isopropyl alcohol and liquid dishwasher soap.
Usually works. Keep the plant isolated from the others.