I have an IQ-X and Igaro on my audax/touring bike. The IQ-X is great and being able to mount it upside down is very useful (if you like a front rack). I run the two in parallel, so you don't need to switch. However, I've found that you can't run them both together if you need full brightness from the IQ-X while charging something. The dynamo (Shimano DH-T780) just can't give enough power for that. I guess you'd have the same issue with any set up on that front.
I have an IQ-X and Igaro on my audax/touring bike. The IQ-X is great and being able to mount it upside down is very useful (if you like a front rack). I run the two in parallel, so you don't need to switch. However, I've found that you can't run them both together if you need full brightness from the IQ-X while charging something. The dynamo (Shimano DH-T780) just can't give enough power for that. I guess you'd have the same issue with any set up on that front.