When it comes to giving advice I try to keep in mind what I know from hands-on, what I know from other people I consider knowledgable, and what I know from research. Then there is popular sentiment, which isn't useless as it can expose patterns but isn't a good basis.
I recently answered on a different forum about carrying a SIG 238 in Condition One and why I thought it was how you should carry SAO even though I freely admit I'm more of a DA/SA guy.
My general thoughts on carrying is that your gun should be in a state where it is reasonably safe to reduce the chance of a negligent discharge but accessible enough that it can be brought to bear quickly.
For single-action, that line seems to be Condition One. Hammer cocked, safety-on. This means I wouldn't ever consider anything without a 1911 safety because it needs to be easily disengaged.
For DA/SA I'd say hammer down on a chambered round, safety off.
DAO, round chambered and if safety is present it is also off.
Obviously some guns have grip safeties or other measures but in general my philosophy is your weapon needs to be ready to fire but you shouldn't be running around without minimal safety measures. For double-action, the long trigger pull should help reduce chances of a negligent discharge. Also, you should have a holster with a trigger guard, even if you pocket carry.
Does any of this seem unreasonable? I'm trying to vet this advice before I give it again. I know Condition One makes some people nervous but it seems like the best way of carrying single-action to me.