why not try that go pro camera you have. aim it at the fuel pressure gauge and go for a short test drive. include idle , economy cruise and a very brief high load.
no need to go on the express way or any high speed driving just show a range of loads. I maintain the fuel pressure should "mirror" engine load. low load low fuel pressure , high load higher fuel pressure. did the fuel pressure vary?
If NO , loosen the lock nut on the regulator and back the adjustment screw out until fuel pressure drops to around 28-30 psi. Re tighten the lock nut. now a short test drive keeping speeds and loads low. did drivability inprove? Remember that leaned the fueling so no hot rodding. now restore the fuel pressure setting and decide what to do. careful around the opening in the bellhousing and the rotating flywheel / clutch and don't let the car roll away on you. ( wheel chocks) Not trying to be insulting , just safe.
If you have a oxegen sensor in the exhaust it will try correct the mixture. no action needed just an observation.
Again see if you can get any information on your regulator.
Now you should know enough to talk to your tuner , or some one that knows your system.