I spent months getting those field notes and the last couple were just not dropping for about 45 days of back-to-back grinding. It absolutely sapped any little fun Bozja had to offer (which wasn't much to begin with for me as I prefer Eureka to Bozja for several reasons) but the mount was the carrot on the stick to get me to be there. I didn't want to do the duels initially for the same reasons: You have to master the CE that leads to them (can't suffer avoidable damage to qualify for the duel) and even if you do (which the CE leading to the duel takes a bit of time to spawn in the first place) you might not even get the duel over someone else. And, to top it all off, all the duels come with cheap mechanics requiring you to either cheese the fight to win or know exactly what lost actions to bring and when to use them to avoid the cheap one-shots they all have.

To save myself some sanity and an enormous amount of wasted time in Bozja, I did the duels. Used the cheese strats you can find only to complete them on the first try. As long as you qualify for the duel, you'll get notoriety which'll increase the likelihood of you being selected. Or you can purchase priority deployment for clusters (I think they work for duels. I purchased them before each duel CE spawn and always got selected even with only 1 notoriety. Anecdotal to be sure, but it's the experience I have to go off of).

The drop rates are horrible and the content they drop from aren't frequent enough to make it enjoyable. It definitely seems like it was designed to keep the place populated and to incentivize you to grind for other things while you get the field notes. While that may be so, I got all combat jobs to 80, bought every single thing possible with the clusters, every single piece of gear you can get with bronze, gold and platinum coins, unlocked every single lost action, capped out on several lost actions (which I didn't even know you could initially), fully upgraded a tank set of bozjan gear and got halfway through upgrading the maiming bozjan set as well (for dat haste). I did all that before deciding to just aiming to get the notes through the duels because the drop rates are just that bad. Result? I got them all in less than a week.

Please, take my advice. Look up the cheese guides for the duels you need for your final field notes. Use the cheese strat. Do the duel. Preserve your sanity and time.