If you don't want to go with a helmet mount then they will both have to be frame mounted.
To get a clear image you will want to use aftermarket mounts, my suggestion is a RAM system.
...
If you need more information about which mounts to buy and were from, let me know and I can provide product codes. Note you also need to think about memory cars, 16gb on amazon for less than a tenner x 2.
This has helped a lot. I'm ordering the part numbers as in description...
View: http://youtu.be/GIBqJ1r768Q
on TVL's video.
Anything I've overlooked?
Ta.