Phal potting question

[labyrinth1959]

I have a Phal that desperately needs to be repotted. Right now it just finished a beautiful bloom period. It is in a 4.5" pot, badly root bound and it has already put out a new fast growing 4" leaf. I will be putting it in a 5" clear plastic pot with lots of small and large vent holes.
I have two bark medium to choose from; one is very coarse, the other is rather fine with a lot of variance in size and shape. The larger chunks tend to be long narrow pieces and the smaller pieces can be very small.
Question 1:
Which medium should I use? Or should I mix them together?
Question 2:
Should I thoroughly water the Phal before re-potting or re-pot and then water?
Question 3: If I re-pot dry, how soon should I water the plant?
Question 4:
Should I attempt to re-pot with the roots on or near the outside of the pot or more towards the middle of the pot.
Thanks in advance for the suggestions.