In my experience a straight armbar is sort of like a kimura, but when you switch off and straighten their arm to put the pressure on the elbow. See Hughes vs Gracie when it looked like his arm was going to pop, or Sean McCorkle vs Mark Hunt.
Mir vs Tank. He has another of the "one time" subs with the inside shoulder lock. A toe-hold puts pressure on the ankle, not the toe, in case you were misunderstanding.
I couldve sworn the Guillotine would have the highest percentage. Glad you posted this though its pretty cool to know.
its amazing how little the kimura gets used. it has so many applications. its a fiercely undervalued submission imo.
the more you fold the elbow the easier it gets but i think its more to do with the gloves not allowing for good control of the wrist.
I always called any armbar for which you're NOT using your hips to apply the finishing pressure as a "straight armbar".