I'm part of the original IOS crew since 2003.
www.illinoisopenseries.com
We decided to add 2-6 temp holes on every course. We've tried to make them the best we possibly can. A few holes have actually been the signature hole on the course. We've used rubber tee pads and Mach 2,3,5or Discraft Chainstars baskets. Sometimes they are better than the baskets on the regular course.
We are players running events. We run events we want to play. We want a lot of players in our divisions and the biggest possible event out there. I have yet to run into 1 tournament director that spends all this time preparing for an event then says "I hope this event small and doesn't fill". If they are capable of getting 90 players over 72 they are going to do it.
2 rounds of 18 holes in disc golf is not very much golf. We have tournament players that are in it for the long haul.
For a few years our player base expanded where we were filling each day at every event. Players refuse to preregister so there is no way to predict attendance. Many events in my area fill. 5'somes are common as well as temps. Back in 2006 I was able to play 2 rounds of 27 holes with all 5'somes. Avery Jenkins didn't like the 5 hour round!
http://www.pdga.com/tournament_results/11758/Open
A few years ago I revived the Sinnissippi Open in Sterling, IL. I ran a 1 day event on a Saturday. I had 24holes set up and filled 5 somes. I put in a floater group of 5. I had a car load of guys who drove from STL which is 5+ hours. They were at the cutoff point where it was full. I had an extra basket in the car and set up a 25th hole. They thanked me so much for letting them play. I had to turn away another 20+ players. With 4'somes I would have capped out at 100. I ended up getting 25 more players in.
http://www.pdga.com/tournament_results/13436/Open