Biquads and dynamically changing sample frequence

I am currently writing a small refactor of the BiquadFilters.h to allow for easier integration when having multiple filters. As well as adding new filter types.

A couple of questions have come to mind:
* Any thoughts on how to handle changes in sample frequency? Is there any resamble going on, or do we need to re-calculate the filter coeffs?
* Where can the overall gain be adjusted? I believe that I am experiencing vast amounts of clipping