Toilet rough-in questions

Hello,
In preparing a bathroom remodel in California, I have a few questions on the toilet rough-in that I didn't find answers to in my intro plumbing books or searching the archives. Any help would be very appreciated. I will of course check with my inspector for the final say, but I would like to be a little more knowledgeable before I approach her.
Cheers, Wayne
1) I'm going to be using ABS for the DWV. What are the pros and cons of a solid ABS toilet flange versus one with a metal flange?
2) Should the top of the toilet flange be flush with the finish floor, or 1/4" higher? I've heard both.
3) Does the use of a sanitary cross to connect two toilets to a soil stack force the soil stack to be 4" in diameter? If so, should I just make the toilet drains 4"?
4) Every diagram I have seen shows a closet bend right beneath the toilet flange. Can it be lower? I'd like to drop below some 2x10 floor joists, as I have plenty of altitude and room in the crawl space.
5) For that matter, is using a closet bend a requirement, or is it just a convenience? I can imagine using a 45 degree bend and a Y connection.
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These are mainly my experiences...

I use a metal flange that can be adjusted by spinning the outer metal part. Let's me slap everything together and adjust for proper orientation later. More importantly would be the wax seal I'd think.

I've heard both as well. I go with flush. You can always stack wax seals if there's a problem.

Don't today's low-volume toilets require 3"?

Dunno. I've often wondered if this is by design of the toilet or house.

Again, dunno. 2x45 would be more gradual but would introduce more edges for 'crap' to get stuck on (how much would be caught in the lifetime of a house is another question). I'd guess the answer to #4 will help here.
Like I said, only my experiences. Darryl.
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Wayne Whitney wrote:

You better run all this past the inspector, esp. Calif.
In general, using a closet bend and entering the stack with a San TEE (rather than a WYE) eliminates the necessity for a vent connection to the closet (no fixtures above).
If you're doing back-to-back closets (San Cross), the stack may need to be *at least* one size bigger than the branches. They may not permit a cross here at all. That will mean 2 separate WYE's or TEE-WYE's, each with it's own vent connection.
YMMV, ask first... Jim
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