What size is the tank that the light linked to is on?
And, which version of that light do you have (bulb length / wattage)?
Some rics will split quickly, while others will continuously grow additional mouths without actually splitting into multiple individuals. Some people feed them small meaty foods to encourage them to grow and split, although I've never wanted them to split any faster than they already do for me (which isn't particularly fast). A few that I've had in good current have "walked" across the rockwork and glass, tearing off little pieces of their base that grew into new rics. When they would do this, I could count on 2 - 3 new rics a week (although they certainly start out quite small). This has mostly happened with the R. yuma variety and not so much with the R. florida kind.
I've read of people taking a sharp razor blade and cutting a ric in half (especially if it had multiple mouths -- leaving a mouth for each half), but I haven't tried it myself (again, not in a hurry to have more of them). Some places I've seen say to just cut all the way through, others suggest only cutting it enough to encourage it to split. In the latter case, I've read of people complaining that too often the ric just heals back up instead of actually splitting for them.