Which DTD?

My pages are written mainly to HTML 4.0, but to get seamless frames I have to use both IE & NS extensions which does not validate using the 4.0 Frameset DTD

How do I indicate to the Validator that I wish to use the following Border & FrameSpacing extensions?

2.  Another page is 4.0 Transitional//EN
but reports an errors on the <EMBED tag and its Attributes  My own Machine Based Validator accepts these No problem for HTML 4.0, and text books that I have (HTML The definitive Guide) does not indicate validation problems with EMBED.

Which DTD should I use for this page.

If you can help Please e-mail me to
pjb@philipbailey.u-net.com