hey bamc,
i'm doing my phd part time too and working full time. currently, i'm dedicating at most 1H/day and on fridays, i assemble my findings for the week, which takes an additional hour or two. i try not to disrupt my weekend. it's for taking a break. hehe
it's not the amount of time that u allocate for research that determines progress, but rather, how u spend it. we gotta learn to optimize our research technique to be able to accomplish part time research successfully. i'm hoping to graduate with my other friends who are doing it full time. ambitious but doable iA, if done the right way.
then again, i'm doing my phd for engineering iA, so some might argue that the time allocation may not be suitable for other disciplines.. certain phd specializations like biology, veterinary etc that involve living entities may require more time for the experimentation. for social sciences, interviewing people can be time consuming. however, u can still optimize time by using surveymonkey or interviewing people through skype. hehe
there are many ways to do research :) . doing it part time just implies that we gotta be more creative about how we *invest* our time. above all, we must learn to have FUN with research. passion keeps the NOS in sufficient supply (metaphorically, i hope u know what NOS is for, LOL) and what's the point of juggling work and phd if we're not having fun aye?