I think this has been more of short notice advice or I could be mistaken? I agree if you have the time to learn techniques properly than do so, but it seems OP is strapped for time, partners and coaches and with out someone showing you how to check or do techniques properly might as well fall back on toughness and haymakers.
Lets face it though, amateurs hardly throw proper thai kicks anyways. The posture is all off, most drop guard and barely crossface. The overhand right on low kicks is there all day even on some professionals!
True, however he is having the fight in Thailand, where low kicks are practically the first thing they learn