A Rotax 912, with vegetable oil injected into the exhaust, will make smoke.
It will also make a sticky mess of the belly of your aircraft, as well as cut into the gross carry weight of your airplane with the added equipment and tanks. Probably not advisable.
Skysmoke is not in business anymore. Besides that the smoke oil injector was brass and burned up after a year in use and the pump from them was leaking after two years in use.
I bought a new oil injector at www.smoke-system-helper.com (the pump he sells is too big for an RV-12).
The pump I have now is a waterpump; Shurflo Nautilus 12v. I don’t have a solenoid installed, works ok without.