A cleverer ejection seat could track the tail and body of the craft, and adjust the rocket force based on the trajectories in each case.
Then you don't have to use enough force to avoid the tail in every case, but merely enough force to avoid the tail in this case, which will normally be far less.
Yes. And if someone is curious why are we using solid fueled rockets in this application:
The big benefit of solid fueled rockets is that they are very reliable, and require no maintenance. They are basically a big “candle” composed of a mix of fuel and oxidizer. You can lit it a day after it was made or twenty years later it will work the same.
The liquid fueled options have valves and other moving parts which can jam, corrode and degrade with time. So it would require frequent maintenance and would still be likely less reliable than the solid fueled variety.
Of course there is: whatever event warranted the ejection. The seat/canopy mechanism is relatively localized within the aircraft, adding one more system to fail is perhaps frowned upon in this absolute last-chance survival system.
Then you don't have to use enough force to avoid the tail in every case, but merely enough force to avoid the tail in this case, which will normally be far less.