I will be getting a Roland UA-55 Quad-Capture and will be hooking up to use a stage piano, I am just wondering which way would be best to hook it up , my piano has midi in and out / Aux in with two slots R..... and the other L/L R. So i take it i can connect with a jack 1/4 lead or a midi cable, but which would be best ? also i have spare jack leads from my guitars would i need to use two leads the aux in R and L/L R and connect them both to the audio interface ?