Are there any good resources out there that will help me getting started with higher power solid state amplifiers? Any good books, online resources?
Back in the day, when semiconductor manufacturers generated paper manuals, Motorola created a group of Application Notes and Engineering Bulletins on Linear Amplifiers. Here are a couple of them.
EB-63EB-27AAN-762There are a lot of other ones archived on the internet. I have the original manuals. Many of these designs were scooped up by the CB crowd to create high power amplifiers. They are actually good designs. I have one that puts out 130 watts with 5 watts input and covers 3-30 MHz. Although, I did have to add some input/output filtering and change the keying.
While these aren't Class-C they should give you an idea of what's involved.