hardwoods are not prone to toxic smoke. i think maybe you might be thinking of green wood. while green wood is anymore toxic than seasoned wood, green will impart a more bitter flavor. of course if you cook at a higher than most temp, then this becomes less relevant. now i think you will see many different opinions as posts, but if nothing else, go with what you are comfortable with.
as far as adding wood at a comp, the majority of folks like me that cook strictly with wood, we just add as needed. once the bed of coals is established, adding wood at the proper time has minimal effect on the temps. also i have seen folks bring a small charcoal grill in which to pre-light their coals over. and yes those folks are cooking mostly with briquettes/lump.
