If you've done several flushes, there's no reason to continue doing them every oil change. Perhaps every 4th or 5th might be better. You risk diluting your oil and causing seal and bearing damage by continuous use of flushes.
I would use Valvoline Maxlife in either 10W-30 or 5W-30 depending on your climate, as we are approaching winter. In the south, the 10W is fine, but if there will be truly cold weather, a 5W would be advisable. Maxlife has given many people good results and is readily available. I see no reason why a 5,000 mile interval wouldn't work. More expensive oils are intended for extended intervals, which are not advisable until a used oil analysis has been performed to gauge the fitness of your engine. The seal conditioners and additive sets that make an oil 'High Mileage' will basically perform the same tasks regardless of name brand or price.
There are many people who will advise using this or that additive. In certain cases there are problems that can be solved by the use of these, but I see no problem in your post that indicates the need for any fix.
The idea that a high mileage car has a need for additives due to it's mileage is a common misconception, and a difficult one to resist. After this many flushes, I have no doubt that your engine is pretty clean inside. With occasional use, as mentioned above, and in conjunction with a good HM oil such as Maxlife they will continue to serve you well.