Previously I imagined that I will leave my rusted PST intact for a couple of weeks before diassembly, but after the testing on last Saturday, the rust seems affecting the performance much by dimming the image by several factors (20x difference in terms of required exposure time), so I'd rather do the modifications first, to fully exploit its potential.
I just bought a belt wrench during my lunch break today, it's slightly more costly than I heard from local friends, but I assume this one should be of better quality. I'll try it out tonight to see if unscrewing the parts could be an easy job with it or not.
First step is to unscrew the tube, second step is to unscrew the etalon from that black body. I shall see if a 1.25" tube would be enough to cover the etalon, and then how the 1.25" visual back should be made. Finally, time to make a better illustration about the solar filter cell as well. It's simply a piece of relatively thin metal sheet rolled around the existing cell, and to add thumb screws to fix it on any telescope objective.
Really no need to wait for April as originally planned.
For indoor remote usage, I think a deep red 52mm objective filter will make my Borg 45ED II as the replacement OTA, let's see.