I'm about to finish the Dave Morris weight training preparation phase and thus I'm almost ready to do my 1 rep maxes. Quick couple of questions for those of you who've already done this...

Did you do them all in one day, or did you spread them out over a couple of days? Also, how much rest did you take beforehand (1 day, 2 days, more)?

Any other advice before undertaking this challenge would be greatly appreciated!

bock

Go into the gym with fresh legs and get warmed up, really warmed up! For each exercise I did a couple of warm-up sets with relatively light weight, gradually increasing. Then do a weight that you estimate might be your 1RM. If you can do more, rest a few minutes, and then do another rep at a slightly higher weight. If you can still do more, rest and repeat.
Also, do you use a spotter? If not, you may want to consider an assisted squat machine. I preferred to use the Smith Machine for squats as I was scared of injury with that much weight.
Before you know it, you'll be doing a short set of what used to be your 1RM!
Does that help?

For some exercises (esp squats) I wasn't about to try a 1 RM. There are some forumlas that you can find online that estimate 1RM based on doing 2-5 reps.

So if you do 2 reps, at weight X, you mulitply X by the corresponding factor to estimate a 1RM.

It is of course not as truly accurate as a 1 rep max, but it gets you pretty close, and you can always adjust weights up/down as needed in the gym.

Here is a couple I just found using gooogle
http://www.engr.mun.ca/~butt/training/coefficients.html