Sorry for replying not asked, but my personal experience (60W increase) was 97% intervals and progression to 80 min TiZ. I was doing threshold 3x a week but that had an impact (or rather lack of) on my dynamic power burtst and muscle fatigue over ftp (my 5 min power and vo2 max was also improving but the problem was muscle fatigue).
“My” solution (and it worked wonders) was incorporating once a week SST with 30s power burts. You can also do threshold with 5s-15s burtsts. Working couple % under FTP has a huge (positive) impact on recovery. I have created some short experience in this topic: