I simply let aticonfig generate the xorg.conf for me, nothing changed there. (aticonfig --initial -f --adapter=all)
I guess that little extra MH/s isnt really important. At this point it would be better to look for some real-world effecting factors, including better cooling, network latency (better pools) to reach a higher real hashrate
Absolutely. I'm just following a half-way scientific approach, fixing some factors and then trying to maximise others (in this case hash rate). Besides, maxing the hash rate is fun.
When my power meter finally arrives I'll be looking very carefully at power consumption and may try to max MH/J before returning to a compromise which takes into account the very high value of mined BTC versus the value of the consumed power where I live. I've planned ahead to this end a little by investing in a fairly effinient (90%) and exceptionally quiet power supply. Undervolting is a consideration here too.
As for the pools, I've always been a solo miner and my circumstances are such that there is no reason for me to change. A friend of mine is pool mining in Windows with BTC guild and has had much trouble in the last two weeks. multiminer solves some of these issues but he's not tried it yet (and I have no reason to).
Another very important factor for me is noise. My miner has to live in my room and I value my sanity far more than the BTC it produces. I replaced the stock coolers on my cards with Zalman VF3000As (Caution: these coolers are not designed for these cards). Combining this with no overvolting and I'm able to run these cards at high clocks and with 40% fans (which are very quiet). When the stock coolers were still attached I needed to run them at 80% for reasonable temperatures and this was very noisy indeed (be wary of 100% on the stock coolers, many people have had problems with the fans dying on these cards).