What would be some good excercises for 4-way independence,
Hey Brian, welcome to the forum

Hmm... "4-way independence"... some good examples can be found in this book:
http://www.amazon.com/exec/obidos/tg/detail/-/0769233708/ref=lib_rd_ss_TFCV/104-5687360-8331121?v=glance&s=books&vi=reader&img=1#reader-linkand also how do you keep track of multiple time signatures while playing?
There is no simple answer to this, it should come with practice... Some times it takes month of daily practice to get a 10, - 15 second composition right

So my answer to this: practice!
Hope that helps
