Your PCP is correct. The frequency experienced on bupropion would indeed fall into the "problematic" range. I'm impressed you can tell a PAC and a PVC apart from how they feel. I doubt most physicians could do that.

Have you ever seen a cardiac electrophysiologist to determine the reason why you are prone to PAC/PVC's? Or had any kind of holter/event monitor to get a good read on these over a span of time? If not, it wouldn't be a bad idea.

As far as beta blockers, your best bet would be metoprolol succinate. It's the most beta selective of the common beta blockers and has QD dosing. It should effectively ameliorate the increased PAC/PVCs that you are seeing since it would block the increased beta1 tone due to the action of norepinephrine on the cardiovascular system. Do not let anyone try to prescribe you Inderal LA or any other long acting form of propranolol, it can cross the BBB, and is well known for increasing depressive symptomatology. Metoprolol is not capable of crossing the BBB, so it has no depressive impact.

How well you tolerate beta blockers can determine whether your strategy will be successful. Some people find adapting to beta blockers very difficult, and some have no difficulty. How easy or difficult it is seems to be idiosyncratic. If you have any anxiety you should see it improve on a beta blocker, so there is that. One thing to keep in mind regarding beta blockers, they are only competitive inhibitors, so if you press yourself hard enough, it is possible to exceed their blocking potential by flooding the beta receptors with catecholamines, which would cause it to fail, and the effect of doing do can be unpleasent, at the least. So, while on a BB, you need to get used to a "new" ceiling on your HR when it comes to intense activities. It can take some adjustment, but it shouldn't have much of a limiting effect on athletic activity after the adjustment period.