Well, thanks for forcing this "lurker" to join up. I have a 1983 that I keep bringing back from the dead system wise. It has only 4 jets and the holes for the blower unit. While smaller, it looks a whole lot like yours. I once read if the shell is good, no leaks, etc. it's doable!
Since no one else has replied, I thought I'd put in my 2 cents. Personally, I wouldn't worry about extra jets, etc. until you see what's up. And I'm sure that some of the experts out there are clueless to help you because all we have is a pic of the top of the tub! I'd need to see where the controls are and a pic of the underside of the tub. My PVC is still good from all those years ago, no leaks. I have put in a couple of pvc parts to create shutoffs to make my life easier. My older tub didn't even have a shut off so I could change the filter without draining the entire tub.
I don't have ozone and haven't missed it although my replacement spa pack does have an attachment for it. My topside controls all the air switches BUT the airswitch on top of the tub is still functional and so I just left it there.
So the bottom line is that not knowing anything more than a pic of the top of the tub, I'm no help. Looking forward to side view (where the controls go) and underside.
Just one more thought. My jets use a separate jet pump and I've not found a way to attach that plumbing to the rest of the tub. It works great but again, until we see where the plumbing runs.....