I suggest you start here with the NRA site that defines EVERYTHING for paper target pistol shooting.
Bullseye Pistol Qualification Program
This sorta falls under the "too much info" category.
The first consideration is the pistol match(s) are shot off-hand. Standing single-hand extended. Not as easy as it might seem.
My club has two different "paper target matches" that are commonly called "Bullseye".
Neither one follows the NRA Camp Perry "National Championship" full course of 2700 points (270 rounds).
One is closer to the NRA "target pistol". It is 600 point rimfire, and 600 point centerfire at 25 yards.
The other is a 600 point (60 rds) .22 LR rimfire at 25 yards. This is a popular season long monthly "club match".
Three "courses". Slow-fire, timed fire, rapid fire. Iron sights OK, and optical sights are allowed. Dot reflex is the most popular.
It's kinda complicated, but basically you fire 5 rds, change target, 5 rds. For each course.
That totals 30 rds. So, the whole "first round" is repeated. Ending with 60 rds, 600 point "possible".
Neither of these follow the NRA "real deal", which has slow fire at 50 yds. This doesn't work on our pistol range.
And, I suspect none of us would want our 50 yd. "scores" displayed to the members.
Yes, there is a max. barrel length. I think 7.5 inches ???
Don't know where you live, but explore for any local clubs. I'd think any gun store would "know" for your area. Good Luck !