well, I did the gravel worlds, 150miles and 11k ft of climbing. Started off well and according to plan, 2hrs in my IF was 0.8 and on pace for 8hrs and after 4hrs my IF was 0.75 and on pace for my original goal of 8.5hrs. Things tailed off from there, I really started to feel lower back discomfort, likely due to lugging around a 3L camelback, so I think that played some part in affecting my ability to pedal. Ended up riding way more gingerly and got in under 10hrs of total riding time. 425TSS, 5600kj and 0.65 IF. Trying to balance a feeling of accomplishment (longest ride ever, only have done 3 centuries previously) with the feeling of not meeting my own potential.
Unlike road races, I got something for my effort and suffering, a finishers patch and a neat t-shirt for participating!