Yep, you're going to get hooked and end up hocking your wife's jewelry for more eyepieces.
The good news is that I have found that you don't need the really expensive ones to get great images with binoviewers. You can mate just about any of your favorite eyepieces that you can comfortably use with either eye. Note though, that if any of those are more than a few years old, the newer versions might be made to different specs and won't mate well. The exception would be premium brands like Televue. I can give you some general advice based on my years of experience.
1) start with low powers, spend several weeks getting used to using and merging, then work your way up the power scale as you find a need for it. Although a pair of 32mm plossls will vignette at the edges, they would be a good inexpensive way to get low power out of your 9.25 SCT and 100ED. A pair of 25mm plossls would work well too, with less vignetting.
2) many people have trouble merging at first. Don't get discouraged. If you have troubles at first, practice during the day on stationary objects, or at night on the Moon. It takes a while for you brain to learn how to merge images at high power.
3) eyepieces: I first look for good eye relief, then for lightweight eyepieces. Heavy eyepieces cause balance issues. Some good candidates that I have used are (this list is not inclusive of course) longer focal length plossls, any brand of "ED" eyepiece like the Orion Epic, Stellarvue FMC 23 and 15mm, various Meade 5000 series eyepieces, Smart Astronomy EF19mm and EF27mm. Other very good candidates are Televue Panoptics and Radians, Pentax XF12 and XF8.5.
4) binoviewers are not binoculars, exactly, and you will loose about 1/2 magnitude in brightness. Not an issue with lunar/planetary targets, but adjust your deep space habits accordingly. Viewing dso's through a binoviewer is spectacular! My favorite targets are M31, M42, and M27. Brighter globulars and open clusters are spectacular too.
Putting binoviewers on any telescope is like putting in a Hemi. Have fun!