JSYK: You need tubeless tires and safety beads on the rim in addition to sealed nipples for a full tubeless setup; OEM RX3 tires lack the tubeless membrane and will slowly leak air through the carcass and the OEM front rim lacks a safety bead. A rim lock is also recommended, but not necessary, to keep the tire locked on the rim in lieu of a tube. The stock rear rim is too wide for a rim lock (3.5" vs 2.5" max for rim lock).
I am going to try Tubliss in my 18" front stock wheel and a DIY rim sealing and Excel 2.5" rim with rim lock on my rear wheel and will share my results. Re: Outex, I worry that if one nipple leaked or needed adjustment I would have to tear up the whole setup rather than with sealing each nipple individually with silicone, Seal-All, Goop, etc you can diagnose and repair leaks without redoing the whole wheel. Also sealing just the nipples is much less reciprocating (spinning) weight than sealing the whole center well with tape. My .02
Here's a well-made tutorial on DIY rim sealing.