hey man, loads of ppl use this style of defense. one tip, block the the wigth with right glove (parry) meanwhile ur left hand is low making a cross like guard.
watch tua v ike ibeabuchi on youtube to learn how to do it.

George foreman used it when he returned to the ring. watch his fights against holyfield. it is good for anyfighter, foreman and holyfield used it good. but be careful, u can get outboxed using it cos ur too busy covering up.

my point is that u can use it if foreman used it. i think foreman is also 6'4. btw u also blocked right handers with ur right hand, jus watch the tua fight, he catches straight lefts and rights with his right glove or jus covers up in a shell. i hope i helped