I would say that the Gina card probably has a much better crystal in it for locking sample rates. I would use it.
I am not too sure though that you need to worry too much about it. You are probably just running the Yamaha cards output to a mixer and mixing the midi stuff there with the stuff coming out of the Gina card? If so, as long as all the music sounds like it is in sync, no need to worry too much. Plus, to truely lock the crystals in both cards, you would have to have a connection between them that deals with this.
Good luck.
Ed
