Here's an interesting variation on the guillotine choke- doing it while flopping to half guard instead of full guard. Now, I firmly believe finishing the guillotine in a solid closed guard is generally the most effective, but the value of this finish and others like it is that it has the chance to catch the opponent off guard and it may force him to think about how to react, giving you those precious couple extra seconds to cinch and finish the submission. I think it might be a good addition to the "BJJ for MMA" category of your repertoire.
-Get Guillotine, not worth flopping unless you have the forearm under the chin
-Throw choke-side leg forward between opponent's legs while flopping backward toward choke-side hip
-As you land, hook choke-side leg to secure position and throw free leg over opponent's back, clamping down
-Cinch choke and finish
*Find a Half Guard Sweep to Employ Immediately if Choke Fails*
Someone with excellent grip try this combined with the S-Grip Guillotine and let me know how it goes.