I think it's better to use the SRX standard waveforms (like saw, square) instead of the internals for your tweakbook tutorials. I am right or what is your opinion about the SRX-98?
I haven't ever tried the SRX-98, however, I do believe it's analog waveforms may have a little more detail compared to the built-in ones, but not by a big margin. Good for you anyway since you will have more different choices.
Can I also get better sounding patches out of your Planetpacks if I change some of the standard waveforms with the Analog Essential ones?
You can't say "better" because each patch is designed specifically with certain waveforms which make the patch sound as it does. You will simply get a more or less different sound if you change a waveform to it's variant in the SRX-98 board.