Whatever training you did for your first 100 miler worked. You took breaks at the right time and 8 hours is not a bad time. You even had the weather with you so you even got that right.

Don't forget the Recovery ride today--Not long- not fast and no effort going in on the legs. Then Monday you can do the ride again to see if it was a fluke

Well done on the ride and throw the computer away- it seems to work for you.