Sega Dreamcast RGB 15kHZ/31kHZ switch with CSYNC

[Piratero]

Hello all. After my successful RGB mod for my lovely N64 (thank you Link83 and viletim!), I feel that I can try on a little easier mod.

According to the wiki, grounding pin 7 will select the 15kHZ mode. I'll be applying this mod.

When I have that switch set to 15kHZ (pin 7 grounded), is there a way I can somehow set HSYNC to ground but somehow cleanly replace the signal with CSYNC (pin 10)? When I switch back to 31kHZ, CSYNC will be grounded and the signal will now be HSYNC. The idea is sort of like a railroad switch.

I have also read that simply using the LM1881 chip to get CSYNC out of CVBS will provide a much cleaner CSYNC rather than getting it straight from pin 10 of the Dreamcast. Is this true?

Also, will I be able to get away with just using 47μF capacitors on each color signal?

Thanks!