What codecs/formats are appropriate for full motion video recording for youtube?
Personally I always choose MP4 container and the H.264 codec as this is also the codec YouTube uses in the final video stream.

What key-frame rates and compression you need really depends on the footage and it's unfortunately close to impossible to give as a generic answer for this reason.

If you have a lot of movements you will need key-frames more often as well as lower compression. This will of course result in larger file sizes as a key-frame is basically a full frame image. There are only costly compromises for this.

How much you need to compress depends on the frame size, the bit-rate that will be used, f.ex. there is no point in compressing at a high bit-rate if YouTube then re-compress to match their max output bit-rate, which again means even worse quality due to re-compression.

If I should recommend a generic compromise it would be to reduce the frame size from 1920 x 1080 to 1280 x 720 instead. A viewer won't notice small details if there are a lot going on in the movie. It of course depends on which eyes one uses, the viewer's eye or the producer's eye. What I'm trying to say is that there is the factor of "psychology" you can use as well. 

You won't need 32 bits. 32-bit is just 24-bit RGB with 8-bits for an alpha channel. You should record and process in 24-bit in cases as this. This will save you some file size and processing time.

Camtasia uses it's own proprietary codec so you will always need to re-compress to another non-lossy or lossy format.

Basically it comes down to trial and error approach, and then experience from that, as each individual video may require a different approach. I saw a similar post here with a link to YouTube guide-lines. Check them out and use them as a basis for settings (especially bit-rate settings).

Also try not to think of the movie in terms of technical perfection but rather how a viewer will view it and for what reason (is the content interesting enough then quality matters less, think news-reports).