I routinely do +15 and higher pugs and if I am forming a grp ask for KS Master and gear IL of 900+ Nowadays its quite easy to get both even if its a skittish.
To OP: tanking a +15 with anything under 885-890 will be tough esp a pug. Some of the pulls are brutal like the enforcers, imp packs and healer has to look for everyone and may not be able to focus on you solely. Did you think of listing as a DPS and forming a grp instead? Pugs are ok to carry a dps if tank and heals are competent.