The OGL itself contains full instructions on using the OGL
Using the Open Gaming License requires following its instructions to the letter. That's the nature of a license: it tells you exactly and completely what you must do to use any material covered by it, and if it's not in the license, you don't have to do it to be in compliance with the license.
One of the OGL's own instructions covers your question. You must include a full copy of the license with your work that used the license:
- Copy of this License: You MUST include a copy of this License with every copy of the Open Game Content You Distribute.
(Of course, you are also required to update your copy of section 15, because that's part of following section 6. And section 8 does require you to indicate what is your product identity [if any], but you don't do that in the copy of the license, just somewhere in your product.)
Regarding length, be aware of what parts of the first two pages of the SRD are the OGL's text and which aren't: everything from “Permission to copy…” to “… The terms of the Open Gaming License Version 1.0a are as follows:” are not part of the OGL and need not be reproduced. Those are part of the SRD itself, and only introduces the OGL.
The OGL itself begins at “OPEN GAME LICENSE Version 1.0a”, ends at “END OF LICENSE”, and you have to copy those parts and everything in between. The font can be small, but it does have to be legible, since anyone using your own material needs to be able to read the license you are letting them use it under. (For an extreme example, the smallest legible size Legendary Games prints their OGL copies in is a 5-point font.)
Page count and font size is less of an issue if you put the OGL out of the reader's way, too. Most (all?) RPG books that use OGL-licensed content put the necessary copy at the end. The SRD is unusual in putting it in the front, simply due to the importance of the OGL to the basic nature of the SRD. You can safely put the OGL wherever you want, but as a publisher, putting it in the back of the book is often ideal — those who need to read it will know to look for it, and those who don't won't be bothered by a surprise block of legalese in their way.