I think the reflex will add a lot, when I glue up my next bow I am going to put reflex in as I think its vital for performance. As you say 78" is long but it should still perform, has it got much early draw weight? It would be good to have you in the EWBS, its pretty competitive at the minute with some very impressive bows being made. I use Richard Head's machine made bodkins for my standard arrows, its the only arrow that doesn't have to have a forged head.
On a side note Bamboo isn't allowed in the EWBS unless its with a flight arrow, so the current distances will be set with Hickory backs.