From a reconstruction perspective, there is no big difference in uploading long sequences as a single one or two. Internally, we align different sequences to each other anyway.
The only thing that is not advisable are very short sequences. We use the fact that images are in a sequence to group the processing of those. Having very short sequences can limit the quality of the reconstructions.
That said, after say 50 images, it does not make a big difference. As @GITNE guesses, we currently process long sequences in chunks and therefore the total length of the sequence has little impact on the result.
Keep in mind though, that the way images are processed could change in the future. So the choice of the sequence length should be independent of it. If you are capturing images as a sequence, upload them as a sequence and don’t worry about how long or short it is.