Unrelated to the overheating I would switch the stat to a 180 as a 160 is a drag race only item & 180 or above is needed for proper atomization & a 160 greatly exacerbates engine wear. The stat might be partly stuck. Rad might be partly plugged but you do have alot of of radiator but I would check it. I have never actually used those water wetters but I've never had a need to & I consider them snake oil tho I'll concede that any type of "water wetter" would slightly help heat transfer from the metal to the coolant. I think a few drops of dish soap (what I use) works just as well. other possibilities: lean mixture (vac leak). block plugged (not likely). way retarded timing (stuck weights) not likely. bad clutch fan. collapsing lower hose. slightly blown head gasket/warped head/deck. Holler what it turns out to be