What is "pegged"? If it is 60 that is OK, if it is 80+ that is not. I would simply put the stock spring back in and move on. The twin cam does not need any additional pressure over what a good stock pump and plate provide. I do see the value of a better plunger that as a precision machined valve to seal better but no value to a heavier spring. One of the functions of the oil pressure relief is to regulate oil pressure when the oil is cold and highest viscosity. If somebody want to spend the money to get a Thayer or S&S 3 stage system now you have actually improved the oiling system by means of better scavenging and gear fit so they provide higher low speed pressure. Next step up a larger sump which helps reduce aeration. Just my opinion in the sea of them. Any internet post with the word "oil" will cause controversy in my experience.
The bike needs to be tuned and the intake seals checked for leaks. I would also do a sumping check, pulling the sump plug after 30 seconds idling, and see if the pump change was successful, no pinched suction orings. But the bike has to idle properly first. One quick check would be to start it, raise the idle, and let it sit at 2000 until it got some heat in it and shut it off. Check the oil on the dipstick and see if it is all still there, same reading on the stick as before the running.