True, and I probably wouldn’t be asking this question if SSB1 had short intervals and SSB2 had long intervals, but they both seem to lean toward a larger number of <= 20min intervals.
No I am not 
This is a very good point.
Since TR base training is so heavily sweet spot focused it may be that I would never be able to get in the same amount of total time in zone unless I do it in smaller intervals. For example week 4 of HV SSB1 has ~5.5 hours of sweet spot. It might be too hard to recover each day if I did longer intervals.
Mainly I’m trying to reconcile everything I’m reading with what TR has chosen to actually put in their plans. Most sources I have come across seem to suggest longer intervals except if you’re new and not able to do 20+ minutes at a time. However, I think those training plans probably would not include 5 sweet spot days per week. TR seems to be an outlier on that. Maybe because they are trying to maximize the benefit that you can get in just 10-12 hours whereas a lot of books and research on competitive cycling assume you are doing more hours than that which probably means more zone 1/2 time and a more polarized weekly schedule.
Related thread: Sweetspot interval length - Short vs Long