I think what folks are suggesting is that what string gauge you use is up to you. Notwithstanding the SRV example, there
does seem to be the implication that you might want to go with a lighter gauge. Why don't you split the difference and go with 10's?
That said, if you choose to stay with the 11's, that's nobody's business but your own! :)
As far as set up goes, yeah, you can really mess up your guitar, but on the other hand, this ain't rocket science either. With some careful study, you could approach it on your own. For myself, I like to see something done professionally the first time, then I know exactly what I should be shooting for. Perhaps you could do this, but choose some place where they won't mind explaining what will be done.
I may be corrected, but I think the two things you would need to be concerned about is your truss rod adjustment and bridge height. It would be a combination of adjustments to these to fine tune your action from one gauge to another.
Heavier strings will bow your neck more (keeping tuned down will certainly reduce that effect), requiring some truss rod adjustment to counteract that. This is something I hear people talk about doing seasonally regardless of string gauge, but I have never had to. (Then again, I'm not too concerned if my action changes a 16'th of an inch from summer to winter.)
The other factor I would see coming into play is bridge height. You will have more or less tension on your strings depending on the gauge, thus a narrower or wider pattern of vibration over the frets. You would need to adjust bridge and/or individual sting height to compensate.
Question: Are you intent on using the heavier gauge for some reason? You have stated that your abilities have taken a back step since you put on the heavier gauge. That would be all the reason I would need to go back! :)
...so ever since then, I always hang on to the buckle.