-2 meditite
-4 wally's training
-3 oracle
-3 rainbow energy
-2 warp point
+2 wobbuffett (sandstorm)
+1 TV reporter
+4 fast ball
+3 multi energy
+1 aquapolis kingdra
+1 oak's research
+2 switch
reasoning for each:
-meditite, + wobbuffett: Your main concern with adding meditite must be Ampharos -ex. We see that. However, at the CC's, your biggest threat isn't going to be ampharos -ex. It's going to be gardevoir, with a healthy dose of rayquaza on the side. Wobbuffett protects better against all three, with a OHKO of gardy, immunity to gardy -ex and rayquaza, and built-in immunity to amphy -ex as well. Meditite just doesn't cut it. It requires that ampharos -ex be damaged quite a bit in the first place, and amphy -ex prides itself on nursing, and thwapping your little meditites with its own wobbuffett. Wobbuffett is simply more versatile, a better tank, and harder hitter against a wider variety of decks.
-wally's training, + fast ball: You lament your overdose of supporters, and here's one solution. Another would be pokenav, in which case you can reconsider the oracle subtraction above. If too many supporters really isn't a concern for you, then Professor Elm's Training Method is the way to go, since it is superior to wally's training in a great many ways. You're only running one evo line, so fast ball is a spiffy way to go.
-3 oracle, +3 (other draw cards): Oracle is great, but a tad slow unless you've got, say, delcatty or pokenav to take advantage of it. By increasing your total number of oak's research, you've increased your general card draw. TV reporter isn't bad, but that's what I'd take out if you decide to go 4-4 on the oracle-pokenav. Otherwise, bump TV up to four too, insuring yourself 10 cards worth of pure draw engine. That, combined with the fast ball and dunsparce, should be enough.
-3 rainbow, +3 multi: If you're going to run tech pokemon that only require one variant energy (meditite and wobbuffett both fall into this category), why add needless damage counters?
+1 aquapolis kingdra: It's energy transferring ability is too powerful to not be used here, especially given that you've got three nurse already in your deck. Also makes wobbuffett that much stronger, since you can surprise with it (lay down wobbers, transfer energy from active to benched wobbers, switch, get the knockout).
-2 warp, +2 switch: The idea of throwing all of your eggs into one basket seems a bit risky to me. There are plenty of situations that crop up wherein I'd rather not let my opponent switch out his active at the same time I switch (see above usage of energy transfer to the wobbuffett...doesn't do you any good if, during the switch, your opponent gets to pull back his or her gardevoir -ex, wobbuffett, or whatever you're trying to attack). I kept it 2-2 just to give you that option, in case you need it.
Hope that helps, and good luck.
Other stuff to consider: Does high pressure system REALLY help you more than, say, a crystal shard or two? Or more card drawing? or a few more switches? Or another dunsparce? Or that fourth Nurse? You run four switch cards already....
Hope that helps,