Graco 4900 HVLP unit

I just bought a Graco 4900 pro-comp that is a year old and never had paint run through it. It looks like this unit is designed for uses a remote can so the gun can be held at any angle. Few of questions if anyone can help.
1. Can this gun be changed to use a pressurized cup instead of the remote can?
2. I have an old pressurized cup but is is not off of a Graco nor HVLP gun. Can it be used or is the cup specific for HVLP units.
3. If it can be converted to a pressurized cup can I get a top mount gravity feed cup? Does it need to be pressurized?
4. Does anyone have an opinion on which style cup sprays better, the top mount or bottom mount?

thanks......