Personally I don't recommend synthol... I'm not against the principle, but there are much better products out there.
DAP with MicroBan
That actually has anti-microbial support built in, which I think we can all agree is a good thing.
That will also give you some nice bulging and bulking action, with the long lifetime that you desire. It is also much, much cheaper, at merely three dollars and eighteen cents for a 5.5 ounce dose. Two of those will add nearly a pound to your weight, and probably an inch to each calve. Plus, Silicon is famous for its lifelike consistency.
When your calves achieve the fullness you desire, you can move on to the breasts, testicles, penis, whatever else you want to enlarge for the same low price of three dollars and eighteen cents per tube.
Let me know how it works out!
:stick: