I usually do:
15 min @ 204W
5 min @ 300W
5 min @ 207W
20min @ 275W
5 min @ 175W
20 min @ 275W
10 min @ 175W
Works out to 1:20 and it's all I can take on a trainer. I only do it 5 or 6 times in the winter when the roads are icy.