I've received a ton of help using an old RCX400 on a newly-installed wedge in the other thread you replied to. I've still got a lot to learn, but maybe I can offer some tips from one newbie with a similar system to another.
This presumes the basics of the RCX are similar to yours.
1 - Polar Home position: this is at declination 90° (telescope pointing exactly away from base, where the celestial pole would be if it were correctly polar aligned), and hour angle 0h (telescope points at the meridian; bottom of fork horizontal, midway between hard stops). In this position, the tube is upside-down with the finder on the bottom.
2 - To find HA = 0h, rotate the fork so that the inner and outer reference marks point are aligned with each other. Once you get close, rotate the hour circle and move the telescope so that one of the hour lines is lined up with both.
3 - 2-star alignment should allow you to pick your stars, just like it does for alt-az. It will show a star when you start the process, but use the Scroll Up and Scroll Down buttons to select a different one.
4 - My understanding is that Calibrate Home isn't used for polar alignment. Your experience suggests that this is correct.
5 - So far, our attempts to do alignment have been somewhat successful. Final pointing has been close, but not as accurate as we'd like, or think it should be if we were doing everything correctly. It usually lands something like 1/2 degree off our go-to target.
6 - When we power up the telescope from the home position after being Parked at the end of the last session, it slowly rolls about 25° (1h 40m) in RA and stops there - with emphasis on the word "slowly". I still haven't figured out why it's doing that. If it's powered up after it had not been Parked before being powered down, it moves both directions in RA before settling at, I think, the same position. Before beginning an alignment, I use the direction buttons to drive it back to 0h HA.
Why it's doing that last bit still needs to be investigated, but for now, we want to put more time working with the equipment. It's at our club's observatory about an hour's drive away, so it's not easy to just experiment with it a lot, which is usually how I get used to using complicated systems.