I don't hunt or do live-shoots with 2F powder in the pan. I use 3f for everything. HOWEVER, I have used 2f literally thousands of times over the last 20-years in reenactments. I will typically file 100 or more blank charges (just powder, no ball) at a weekend reenactment. That's typically two main battle reenactments open to the public, - one on Saturday and one on Sunday - along with a tactical which is not planned for the public to watch on one of the two mornings. Tacticals are typically in wooded areas and over distances which are not easily observable by the public. They can watch, but the tacticals aren't designed for the public, but for the reenactor's experience.
For the first couple of years of my reenactment experience in Vermont, I rolled my own cartridges in powder that was provided by the unit. Usually that was 3F. We actually ended up using the equivalent of 3F powder in cannon powder (forgot the rating) because it was cheaper by the 25-lb bag than GOEX sporting powder. It was cheaper because it was not graphite coated (the "g" in an FFFg rating). That graphite coating helps keep the powder from turning to mush so quickly in the pan because the graphite coating slows down the absorption of moisture. It was kept in cartridges until it was used and didn't just sit in the pan all day waiting to take one shot, so it wasn't a real concern for reenactments.
When I got transferred to Virginia in 2005, the VA7th there provided cartridges rolled from 2F and for the next 10-years. 2F was used in the cartridges for both the pan and the main charge. Just didn't have a problem with it at all. In fact, since it is for shooting blanks and not for hunting purchases where you need consistent ballistics, they would sometimes use "Reenactor powder" in it which has all kinds of sizes of granules. Most are 2F, some 3F, and some 1F. It's like they didn't run it through the grading sifters at all so it had all kinds of granule sizes. Still, had no problems at all with ignition of pan and main charge with it.
Of much greater concern was the lock that you were using and what idiosyncrasies it might have. My first longrifle was a Traditions Pennsylvania longrifle that had a small lock - was the same lock they used on their pistols. Took me a while to figure out the idiosyncrasies of that small lock, but once I did, it was a reliable shooter. Trick with mine (YMMV) was to fill it no more than half full, close the frizzen and then snap my wrist sharply in a clockwise direction. That sent the powder to the outside half of the pan leaving a clear space between powder and the flash hole. Then it worked reliably with either 2F or 3F in the pan and as the main charge.
In about 2006, I bought an Early Lancaster .50-cal rifle from a forum member here with the screenname "tg". He built a beauty of a rifle! It has a swamped barrel and uses an L&R Queen Anne round-face lock. The pan on my Queen Anne lock is easily 4 times larger than the Traditions pan and it doesn't care how much powder you put in it. Fill it up, fill it half full, overfill it so powder falls out of the pan when you close it, it goes off first time, every time as long as you are getting a spark. It's a great lock.
Now I have to note here that there actually is a difference in speed between 2F and 3F powder just as there is between 3F and 4F powder used in the pan. But the speed difference between 2F and 3F, as well as between 3F and 4F, has to be measured by scientific instruments to detect the difference. The differences are so small they are not discernable to the human eye. If you think you can discern the difference, then go ahead and use whichever one you perceive to be faster. It's your rifle and your fun, so do what makes you happy. I use 3F for everything for my .50-cal and am very happy with the performance of my rifle using it.
