It's going to boil down to whether or not the FSDO knows you and is supportive. Think about it - if we worked at the FSDO and someone showed up completely unknown, how likely would we be to sign them off? That's before you even get to the line of reasoning like "what I do for one ..." etc.
The guidance that the inspector is supposed to follow is spelled out at
http://fsims.faa.gov/PICDetail.aspx?docId=8900.1,Vol.5,Ch5,Sec2.
There is considerable room for differing outcomes as between inspectors. For example, there is the requirement that an applicant "...must present documents from an employer, coworker, or other sources
satisfactory to the Administrator... - ie., the FSDO inspector. The reference to evaluating experience on experimental aircraft on its own merit is tucked under a subheading that could fog up an interpretation as to whether it is appropriate to allow it.
My suggestion is to get to know someone at the FSDO, respected in the organization, who isn't likely to transfer or retire in the next five years. After establishing a relationship, pull everything together (look at the procedures cited above and part 147 appendices B, C, and D - have backup for what you are claiming), make an appointment and go through it. Expect to be told "no." That then becomes the opportunity to find out exactly what the inspector wants to see for a "yes." It might not be so difficult. Plug away at it and, in time, persistence should pay off.
YMMV - good luck.
Dan