13.0 A/F ratio is not extremly rich B.T.W., it's extremly lean, especially when boosted & running 15 psi. 12.5 is lean also @ W.O.T.Thats not playing it safe.
I would tune around 11.8 @ W.O.T. @ 15 PSI of boost, (rough estimate)
If you think it is making good power @ 15 psi w/out an intercooler, wait until you install an intercooler & get the tuning correct.
Idealy, 14.7 is good for idle, but sometimes some engines do not like that A/F ratio.
14.7 A/F ratio for cruise is a good area to try & get.
Are you still running 15 psi?
When you say you are concervative w/the timing of 10 degrees initial, how much mechanical advance does the dizzy have?
Just a rough questimate w/your engine & depending on how how boost you are running,, you would want a total of 17-20 degrees total,, again, depending on boost level.
When you install an intercooler, you will be able to run more timing, & w/a methanol injection system, you can run even more timing & that will equal to A LOT more power.
With your exhaust system being really loud,, I highly doubt you can hear the detonation going on. As I always said, you cannot always hear detonation in your engine, that is why knock sensors is key to help save your engine.
