porcelain firing

I've built something which is very, very fragile. It will finally need
firing to 1250C to mature the clay - at which point I suspect that the
clay will be beginning to 'soften' and not be able to take its own
weight.

What I need to do is to biscuit fire to a sufficiently high enough
temperature so that I can safely tuck ceramic fibre in/under certain
areas to support the clay at 1250C.

If I biscuit fire under 1000C, which is what I usually do with most
things so that I can check for cracks, etc, the clay will still be too
fragile/brittle to allow me anywhere near. So, how high can I take it
to have enough strength?

This is unknown territory for me. Help, please.

Susie

ps I hope that soon I'll have a website so that I can post images of the
things I make that give me this sort of problem/headache/learning curve!
--
Susie Thompson
If you can't stand the heat, don't tickle the dragon
to email me replace "deadspam.com" with susiethompson.co.uk