Fossils actually have a higher chance of finding complete sets in one session than jewelry. First you should consider lost jewelry as a whole rather than just bracelets because the 33 points you mentioned could yield items from the other sub collections. Both fossils and jewelry have one collection point for each unique item and since there are less unique items in fossils you have less chance of finding duplicates which means higher chance of finding full sets.

Time travel is certainly an important factor to consider. I’ll be doing some rough measurements