I've used gorilla tape before and while it does work it doesn't feel particularly secure (when deflated the tyres are completely lose and can practically fall off. It also makes them a bit harder to inflate (even using the compressor took a little while to get them to catch).
I'm currently using Bontrager symmetric TLR strips http://www.evanscycles.com/products/bontrager/rhythm-tubeless-rim-strip-symmetric-29-ec037916 on my LB wide 29er rims. The strips fit perfectly, snap in very secure and feel like they were designed for the rim. Just make sure you screw the valve through before putting the rest of the strip in the rim, otherwise you will never get the hole lined up! The same tyres as described above then fit the rim much tighter, they inflated and popped over the strip into the bead hook with a nice bang (at about 30 or 40psi!) and stayed inflated before I'd even put any sealant in.
In my experience, the Gorilla tape does work however the TLR strips are a much better method and I'm much more comfortable running lower pressures without waiting for it to burp.