for example you can build your own progression from a list like this:
30-sec intervals Taylor-3
40-sec intervals Stanislaus-4
50-sec intervals Thimble+1
1-min intervals Freel+1
1-min intervals Bashful
1.5-min intervals Baird+2
2-min intervals Mills
2.5-min intervals Dade+1
3-min intervals Spencer
3.5-min intervals Mist+3
4-min intervals Mist+1
4.5-min intervals Shortoff+2
5-min intervals Shortoff+3
6-min intervals Denali+1
There are a lot to choose from in TR library, that list was extracted from a set of bookmarks I’ve collected. Also think about how many quality sessions you can do per week in a 2-4 week block. Hope that helps.