I am still looking for a cowl for my 73 qq if any one has one.
I am not sure if balancers were ever mentioned,but after years of constructing CG devices and hang balancers I found the "one stop answer" to all the messing around with home made units. It is costly but if you plan to stay in this hobby ( for me it has been 54 years ) this is the answer.
http://www.ezbalancer.com/