I also did it with DS3. However it was very quick! It was from birth, till i turned back around (maybe 2 minutes? as i was on all 4's) and as i turned around and sat down, the placenta came out too. (i actually had the injection dispite my original choice not to, i changed my mind, but as they injected, the placenta appeared, so it wasn't even needed!)

Drs i found very funny... The only ones i saw about it were the peads after he was born, who commented on his mild jaundice, and then said, "oh, you did delayed cord clamping... why on earth would you do that?" Which i then told them the reasons why etc and told them that DS1 was more jaundiced and his was not clamped, and DS3's was clamped within their normal amount of time really as his cord stopped pulsating very quickly!
Most of them just rolled their eyes and went on with their baby check.
None of the doctors brought it up prenatally... i was in the know you midwife program, and my midwife was very happy i was doing it

FWIW i had much less bleeding with my 3rd than i did with any of my others too. If i were to have any more, which i am not, i would have done that again.