Do you have a way to measure the results? ET or something else? Butt dyno?
My guess is that your are fine. I would still experiment in small increments, like +/- 2 degrees if you can measure the results in any way at all. I think most of the time for most situations the optimum total ignition timing is fairly constant for a cylinder head. Most people will say that for a given cylinder head the total ignition timing will not change much. I have seen anomalous results, though. I think low compression and high octane favors more ignition timing. Since you have 11:1 compression I doubt your optimum timing will be off much from the norm.
For example, I once had a low compression (9.3:1) FE with Edelbrock heads and race gas (I don't remember the octane) on the dyno. It liked a lot of total timing. Usually Edelbrocks like 37-38 degrees. We went to 41 and even 45 degrees and gained power before I said whoa.
BBM guys can take over now.
pl