I found with a fixed length fork its best to go for the shorter option, especially for bikepacking where we'er not doing super tech stuff and a lower frontal area helps with head winds and weighting the steering. If the ride is going to be on harder ground I swap back to a 100mm suspension fork but on the great divide a rigid fork was fine.
Having looked at lots of options I found the Travellers Pronghorn to be the best option = length, triple mounts and cost.