I set my tesselation to somewhere in the 40s and it completed the process but wouldn't complete the build. It acted like it was stuck at the end of tesselation even though it had completed the calculations(the counter was 0 for 20 minutes and it wouldn't budge).

Make sure when you build that you have the visibility calculations slider set to off. If it's on you'll get a final build which takes a lot longer(hours and days as opposed to seconds or minutes).