I believe from just very quickly scanning some comments on that thread in the first page or three, that you are to set your set to Picture mode, the pic view to 30 seconds (so it sounds like by default it will not be set to 30 seconds), set the settings of Picture mode to whatever D-Nice has there for the 100 hours of slides (you might want to write down the original settings of Picture mode so you can revert back after 100 hours), and then after the 100 hours, do whatever else he says (likely change to a different mode and his custom settings).
You are not supposed to watch other content on the TV will you are doing the 100 hours of slides.
Personally, I'd make sure it's running the latest firmware (via either wired update or freshly FAT32 formatted USB ((unless Panasonic says different))) before doing anything. Then start the D-Nice stuff.
And Yes, to answer your question, you can just go for 100 hours straight.
Make sure if you break the 100 hours you keep track, and also, that you don't watch anything that leaves static images on the screen (like the program channel monograms in the lower right corner, or 4:3 content in 4:3 mode, or games, or whatever is not full screen w/o a monogram or ticker bar); basically, if at all possible, just do the 100 hours with the slides in D-Nice's post. D-Nice is a top calibrator, whatever he says to do, I'd do it.
Read his first few posts in that thread a few times so you know exactly what he's saying...
Happy viewing!
P.S. If you need to buy HDMI cables, you want cables that are "High Speed" aka HDMI 1.4a; very good place to get them is
www.monoprice.com Don't go to WorstBuy and buy a $80 HDMI cable.
Chuck