Atta Boy, Oliboy! Glad you got it! Now you can go tackle the world! Makes you feel good when it all comes together doesn't it. I continue to do electronics projects because I love it when it all gels and actually works! Very rewarding!
You can use any size jacks you want. Typically people use 1/4" (6.3mm) jacks because the cables are readily available and come in mono and stereo configurations, but that is purely a convenience thing and, I guess, the standard in drum modules.