Power is power. Stick with your lamp’s power ratings, or you’re risking a fire. I’m sure there is a CYA factor involved in those ratings, but why push your luck?
Also, turn the lamp off whenever you’re not using it.
It’s probably OK to use any lamp fixture with sufficient power rating with an infrared bulb. Radiation pattern might also be important. If the bulb directs most of the energy forward (which is typical), just make sure the “light” doesn’t hit any parts of the lamp. That could cause them to overheat.
I doubt much energy is directed backwards, but you might want to check the temperature at the back of the lamp and make sure you’re not going to melt or ignite anything. Keep paper and other flammable materials clear of the lamp.
As for protecting your balls, you can try using something that reflects IR. I think aluminum foil works well for this. Maybe try placing a layer of foil in a dish towel or old T shirt or such, folding it over (for comfort), and placing it in front of your balls.