Thanks for the input, Aemon.
I can't say that I know how to play Udyr, or jungle. So yes, I think I might be underestimating Turtle in that regards. I'm usually the roamer, killing junglers, so I don't quite know what it feels like to be on the other end of the stick.
Anyway, just updating the result.
I'm still using the support runes and defensive masteries.
I still can't find a way to bring down big golem without using Heal. I heard that a proper build can do it with long sword, so clearly there is a way to do it without cloth armor and only 1 pot (I have no idea how though). After that, I still need to B after killing the wraiths, get 3 more pots, and run through the route. I forgot to use the pot and Smite on Lizard (again), leading to a much lower finishing HP than necessary (50%HP, full 30% mana) with total clear time of 4:15. I'm thinking of trying to start at small wolves next time to save that initial 30sec while I wait for Golem to spawn. Should be able to save 5 to 10 seconds that way. Forgot to check my gold though, but I assume there should be just enough for Sheen.
I'm going to give dragon a hard thought. Like I said, I was only concerned with jungle clear time at this point, so it totally skipped my mind. I suppose that with Turtle, it's very much doable at level 4 (?). I'll see when is the earliest time I can pull it off with Sheen. Supposedly though, Mardred should be able to give 500dmg at around 15% chance, or every 7th attack, depending on your luck. I think the best that you should be able to pull would be 2.0 AS by that level (can't say for sure), so maybe once every 4 seconds. If I stance dance between the two stances, I should be able to proc Sheen once every 3 seconds for a measly 40 dmg, and maybe add 2-300 damage from using Phoenix, and maybe an extra 30-40 on Tiger proc (AD bonus) instead of turtle, so advantage Mardred there, but I don't think it will be that much better (damage-wise).
Conclusion so far--at least as far as basic clear time goes, I think there is no disadvantage in going double damage. However, I do see that the traditional build is probably going to be better once you start doing dragons.