Closet Flange Question

I've checked with a few experienced people on this one, but am looking for insight from others as well.

In the process of redoing basement bathroom (new tile, new sink, etc) and when I took off the toilet, the old closet bolts sheared off - nice and rusty. Those old bolts were put right into the concrete. I have everything cleaned up to put in a new closet flange (4" twist-n-set), but it turns out the drain pipe is not perpendicular to the concrete. It's a few degrees off so the closet flange won't sit flush with the floor when it's tightened.

I've been given several different solutions (new closet bolts anchored into concrete, attach the flange tight but not quite flush) but am wondering what others think. When I take the rubber gasket off the flange, it will sit flush, so part of me is wondering if there's something else that could be used to create a seal between the flange and pipe. Then I would just have to anchor it to the floor (without stripping any tapcons...that's a whole other issue). Thanks for any insight.

Would one possible solution be to secure the flange in the waste pipe and screw it into the concrete floor, then use a waxless ring? Or even just install it as normal? There would be a tight seal between the flange and the waste pipe, but would the seal between toilet and flange be ok? Based on what I've heard and read, this may be the best solution. Input?

I would help if I could, but I know nothing about a "twist-n-set" flange.

However you might get it done, the toilet needs to be bolted to a flange that is firmly fastened to the floor. Your broken bolts might be going into lead anchors, and those can be removed and replaced.

Apart from all of that, think of the bottom of the toilet as being a funnel dumping into another funnel connected to a pipe. Momentarily setting aside the matter of seals, everything flushed from the toilet must *only* be able to go down and never in any other direction ... then the seals come into play to simply keep sewer gasses from ever finding their way up and out around the bottom of the toilet.

You are headed in a dangerous direction if you don't get this fixed properly right now. I would suggest you bite the bullet, get the check book out, and have a plumber deal with this. That flange really has to set firmly on the floor all the way around or you are asking for trouble. The thing that complicates the issue is of course the fact the drain is embedded in concrete and just attaching a new flange will not cure the problem.