Stone setting - emerald cut

I am a newcomer and would appreciate some guidance in setting an
emerald cut stone. I have set a few stones in conventional 4 prong
round settings, but now I have a 8x10 synthetic emerald which will
be in a 4 prong octagonal gold setting. The steps in cutting the
stone seat and answers to questions like should the stone rest
against the bridgework of the ring and how to insure that each prong
is cut to an equal depth?

Thanks, Herb