yeah kick usually sits around 80hz, i find i get most definition around there, going a tad lower sometimes works better depending on whats going on in the bass but never as low as 45-50, as usually that's around where my bass is sitting too, but i couldnt imagine it anyway. Of course though everyone has their own techniques, and surely thats what techno is all about. Doing things others dont.

I tend to play things alot more by ear except for when i need alot more preciseness such as cutting the kicks and bass, i think sometimes sticking to suggested freq's and guidelines too strictly will probably stifle the creativity and you should just kinda go with the flow if you think you've got something really rocking on the cards