100mcg T3 is a pretty high dose to run, especially for any length of time. In some, this could cause some nasty thyrotoxic symptoms. Add clen to such a high dose of t3 and you could really burn your adrenals out pretty quickly and experience some nasty sides. T3 patients often feel fantastic when initially medicated, however, in some with poor adreanl reserves the mood and energy boosting effects diminish as the increased sympathetic nervous system tone increases adrenal output. So, consider supplementing with extra vit C, maybe some 7 keto DHEA and B12.
If you are looking for simple metabolism boost I would suggest a lower dose, something like 25mcg in a divided dose earlier on in the day would be appropriate. Research does show that thryoid meds actually work best taken at night prior to sleep, however, with T3 there can be noticeable stimulation, preventing sleep.
Start slow, with 12.5mcg for a day or two then increase.
If you do decide on a higer dose, use the same protocols. Start slow with periodic increases and space your doses out. T3 can increase energy expenditure by around 500 Cals per day, it doesnt compensate for poor diet, so unless everything is in order, physique wise you may not alter very much.
For anorectic effects T3 would probably not be a good idea as it can make you feel more hungry.