Doe,
We originally started off with 225 grain, but that gun is so light and little it even kicked the snot out of me. My wife REALLY hated it.
As for solid conicals, I believe not only would they kick too much. But as stated, I don't believe you can shoot the heavier ones out of it anyway.
That being said. I need to look at the manual and see how big I can go. If I reduce my load to 60 grains as Surveyor mentioned. Might work out just fine. Worth a try.