Just like you are hearing, there are many things that can effect the effects of clenbuterol.
You can most commonly expect an increase of .5 to 1 degree in body temperature, and this doesn't
apply to your experience... but the basic length to effectively run clen is 4-6 weeks, which is when
the effects will diminish from beta-receptor down-regulation.
Having said that... my experience and results have been very good, however slight shifts in the type
of calories will greatly impact your results.
Calories are calories but I'm sure 3J would know how to maximize your results to get more burn...
I've ran clen with T3 and sweat so bad it was almost comical... and I've also ran the same ratios of the
two with just a slight shift in my diet which greatly effected the results much more than I would have imagined.
Just like halfwit mentioned... you also have a shift in tolerance from person to person as well.
Going back to shaky hands... that is something that I ALWAYS see when I'm on clenbuterol...
... simply writing my name - or texting... "it's all a bitch on clen." 
