I've never shot a 209 primer.
But almost every new gun manual from CVA and Traditions will say that for best accuracy stay between 90 - 120 grains of powder.
The max. charges are reserved for pellets and not loose powder.
For instance CVA recommends IMR White Hots probably along with their Powerbelt skirted bullets.
I've heard that there's CCI magnum 209 primers, yet the Winchester 777 primers are the least hot to produce the least amount of crud ring with 777.
IMO 209 primer systems are made for reliability [especially with pellets] and not necessarily to only make the hottest ignition flash.
Every barrel has a different length and spec's, and even 209 ignition systems have different design details.
MMP makes many different kinds of sabots to fit slightly different bore sizes, and even the Harvester ribbed sabot design is different too.
Now there's a new proprietary Ridgeback sabot design that been invented by Berry's bullets and that's been picked up and being marketed by Traditions only available with their latest Smackdown series bullets.
As you know, there's a lot more to shooting than simply differences in powder or primers.
Personally I would try experimenting with Black Horn 209 powder.
The only detail to note that I've heard is that it can be helpful to snap a couple of caps before loading to foul the barrel or the the 1st shot can be off a couple of inches or more if the barrel is too clean.
And even if using Black Horn 209, it's important to keep the flash hole clean as blowback can narrow it.
That's the opposite of my standard practice which is to sight in for the 1st shot out of a cold, clean barrel. But then I shoot with #11's and American Pioneer 3F.
There's also new star shaped 777 pellets out that slightly increase velocity by increasing the surface area of the pellets, which are 33 grains instead of 50.
Decisions, decisions. You have your work cut out for you, but the max. charge of lose Black Horn 209 powder is 120 grains.
Shoot enough unnecessary max loads of different powders and a person could ruin their scope. Tread lightly by loading with moderation in mind.