Firstly just remember if you do this to your kayak you will comprise the warranty of it.
I recommend drilling the seat, especially as a female as it with lighten your kayak. You can do this to your playboat or creeker and river runner.
Will it reduce the strength of your kayak?
I personal have not experience and structural strength issues in applying this to my kayaks. I look at it as the same as bone structure. This bone is call sponge bone, see image below. While it has holes in it, it remain strong.
I recommend leaving 2cm or 3/4” between each drill hole.
Phillips head screw driver
1”1/4 Hole saw
A good idea is to take picture before you remove everything that way if you forget where bolts went you can refer back.
Have a Merry X-mas, maybe a bit of snow kayaking for some... for me a surf kayak is in order! or maybe a new boat from sainter!