Instead of granny seats, try riding some hills. You stand up 15 strokes to relieve your seated burned out thighs, then sit for 50.
For 25 years, I used a SelleItaliaPro seat. Was fine, because I shift riding position depending on RPM, load, and efficientcy.
Now using a stock CannondaleCaad8 seat, which is fine up to 40 miles seated.
You get a much better workout from the standing position.
Seat yourself forwards for moderate climbs and moderate RPM's.
Seat yourself well back for downhills, and slower RMP's, stretching out your legs.