$.02
Diet soda, etc. is just fine up until 10day or so.
As far as the clen, there are tons of protocols. If you are not using ECA, then I would cycle the clen (unless you have superclen). Also, go with 3+ g of taurine / day.
I would ramp the clen (at least for the 1st time), up to about 120mcg / day over the 1st week, then hold for a week and drop over a day or so. (It has a long half-life and tapering doesn't seem to help the crash.)
I would also do yohimbine hcl, if you can - around 15-20mg / day. work up to this.
Add some caffeine if not doing ECA.: 600mg / day
I would skip the T3, unless you have a LOT of fat to lose. Too easy to lose muscle w/ T3. (Better for reducing fat gain / enhancing metabolism when gaining IMHO.)
Would look like this
Week 1: ramp clen to 120mcg/ day. Tuarine here
Week 2: ramp yohimbine in week 2. Taurine
Week 3 drop clen, add caffeine (and aspirin), continue w/ yoh., taurine
Week 4: Ramp clen in 2nd half, continue w/ clen, caff., taurine
Week 5-6: clen, yoh, caff, aspriin at full strength, taurine
Hope this helps!!!
_Randy