Pretty optimal settings for <20% compression?

[Flux]

I have re-authored DVD-movies with Shrink so that there is only the main movie, AC3 audio, chapters and subtitles.

However I have to compress main movies about 15-18% so one DVD-movie fits to single 4.37GB DVD. I'm using CCE SP 2.50 and latest AviSynth. What are "almost optimal" settings for CCE when compressing <20%?

Sources are all PAL and most of them are progressive and either 2.35:1 or 1.85:1 and it seems that I have to keep black borders so there is compatibility with DVD-players? I have read the "get best from CCE" doom9.org guide but I just wonder if it has general settings and some other settings might work better in "small" compressions?

[RB]

There's nothing special with "small" compression. And honestly, when talking about 15% compression, I probably wouldn't bother with CCE, Shrink/IC/whatever results will be indistinguishable from CCE.

[Lagoon]

I agree 15% isn't something I'd bother to reencode, but I'd still only use IC8, because shrink and others are distinguishable at 85%, for me anyway.