I want to use old jbl 12" d123 extended range speakers on an OB.I might use a subwoofer. The d123's go out to 7kc,where I add jbl 077 horn tweeters. The d123's are 98 db efficient,fs of 40hz,qts of .45,and a vas of 4.5 cubic ft. What size OB board should I use? should it be flat only,or use wings? Thanks for any advice.Rudy( 077 tweeter).