Benji,

I get western red cedar from Home Depot and Lowes.
Searching thru everything they have results in about 2 boards / day, giving me about 40% useage. not good, but it is what I can find locally. Generally I can only find 8' or 10' boards, requiring each strip to be joined on the boat.
I cut my own strips, but I have a tablesaw.
For me the best secret is to cut all strips at one time, making sure as I can that they are all identical - especially thickness. Finger boards are a great help in consistency.
If you are going to use accent strips, final cut them at the same time as the cedar.

I use walnut and poplar for accent strips, but have recently used maple instead of poplar and gotten much better "white" strips.

Have fun