The one thing i have to say about this is to measure 3 times and cut once. If you're installing a flush mount into the surface of the kayak you really need to make a template that the rod holder sits in perfectly. Then transfer the template to the kayak, mark it and cut it out carefully. Flush mounts come in angled and straight types.
Flush mount holder.
Here is a good link to fitting a flush mount Fit a flush mount
Surface Mount
Mounting a surface rod holder like the one above is fairly easy. Find the place that it best suits things like your paddle stroke ( don't want a rod in the way when paddling ) also where you can reach it easily without having to stretch to far and last but not least, Is the place you are putting it strong enough, can you put a backing plate under it the strengthen the hull. There are many , many different types of surface mount holders out there. There is one that will suit your needs and budget, but you get what you pay for
