Going to grad school Change from H1B to J1? or to F1?

[senorfrogs]

I have been accepted to grad school with a full Research Assistanship. They offer me the option to get a J1 or an F1 visa, and I don't know which one is best for me. Since I will be sponsored by the american university, I will not have the 2yr home residency requirement.

This is my story:

04/1999: Denied for a B1/B2 visa
08/2000 - 12/2000: Internship with a J1 visa with no 2yr home residency requirement.
02/2001: Got a B1/B2 visa.
08/2001: Hired in the U.S. with an H1B visa.
12/2004: Renewed H1B visa.
02/2005: Employer started Green Card process (I am not sure how far is it, maybe not even filed petition).

I am single, no dependents. I want to get the visa with the least amount of troubles.

1. Will it be more feasible to get F1 or J1? Will I look "supicious" to the VO since I have been here for so long?

2. How long does it take to change status from H1B to J1/B1? I want to make sure I'm ready to start classes. While the status is being change, can I continue with the employer who sponsored my H1B?

3. I know people can stay up to 1 year after their F1 visa expires, does the same apply to J1?

4. My fiancee and I are planning on getting married sometime, she's american. When will it be a good time for us to do it? I assume once I'm in grad school, right? not before.

Thanks!