Try both, post pics and let us know which one you liked best!
There was an interesting item on a food programme here in the UK a couple of months ago that compared the effects on flavour of dry rubs and wet marinades. It found that the wet marinades only permeated flavour marginally more than a dry rub. Of course the real advice was to brine to ensure juiciness.I’d go with the rub. Marinades don’t do it for me.
Sounds amazing!i've marinated it in zinfandel wine overnight and then montreal seasoning (any dry rub with salt) onto it for an hour at room temp before grilling it. i also do this same process on tri-tips. the wine is an acid which penetrates the meat easily and then the rub is flavor on top of the wine. served with grilled asparagus and real garlic toast (crushed garlic into butter/evoo and fresh chopped italian parsley, in a saucepan and cooked very low to infuse the garlic into the fats/oils) then brush on top of grilled bread (costco baguettes sliced open face). a small amount of wine goes a long way so no need to drown the flank in a bottle of wine. a glass or two is more than enough.