When I had my last observing session, I was very frustrated by the straight-through finderscope on the ETX-90. I noticed there was a Meade right-angle finderscope but it wasn’t for sale anymore. It was out-of-stock at many Internet websites too. I monitored eBay for a while and one didn’t come up for auction. I did some research and found some forum posting for some options. One was to purchase an Orion Right-Angle finderscope.
So, I purchased one. After it arrived, I removed the default finderscope from the ETX-90 but the Orion finderscope was too big to fit in the mount. I then noticed that were mounts available from Orion for Meade telescopes. I had a chat session with Orion and found they wouldn’t work for the ETX-90. The only solution was to glue it to the telescope tube.
So, I decided to just live with the existing finderscope.