> i did do the pre-condition, even though i don't fully understand it from the documentation. but my question is: what if the profile you started with is very poor quality?
The first, pre-conditioning, profile characterizes the borders of the gamut, and the device linearity. It allows for targen to follow something better than an abstract device model when generating patches for a final profile. Abstract model places the patches "all over the place", shooting in the dark. Pre-conditioning allows to put patches "on target", that is within the gamut of the device; and distribute those patches appropriately.
> i'm not sure what's going on with the 2-step precondtion
Just an improvement over the initial device description, plus if the first and second preconditioning profiles differ significantly, it is an early diagnostics of device instability or workflow problems (like not letting the target to dry fully, or wrong parameters in commandline).
> i'm guessing you run create a profile with precond set, then create another one using that second profile?
Yes.
> just a quick side question - you know the physical color checkers?
You mean, do I have those targets we shoot? Yes, I do.
> are the colors on these devices computer generated in LAB space with a certain lighting in mind like D50?
That is a long and very interesting story, you may want to start the reading with the bio of the man named Munsell, and his work of life. The colours are carefully selected from real-life colours and actually named after those colours, except some that are close to printing pigments (sort of real-life, too). The colours were coded in Munsell notation, and later converted to Lab (which is D50) for convenience.
> so it all starts in the computer then and then gets translated into the physical world?
From the above, you can see it is vice versa