SilverWook said:

I guess we would need a good print of Dr. No to compare.

IIRC, Terence Young mentioned something about the day-for-night sequences in Crab Key during his infamous Criterion commentary and how prints would rarely get it right. Presuming, he actually approved the Criterion master or even was watching the master while recording the commentary, the Criterion LD might be your best bet of what's right.

I'm of the opinion, though I honestly don't have much to back it up, that the Criterions are the most faithful in terms of how the movies looked theatrically. Judging by the high contrast and grain, they seem to be from prints rather than IPs, so may have an additional generation of grain/color variation.

Do you think there's any way to tweak the Lowry transfers?

One would need extreme time and patience.

You could probably color correct it relatively accurately with time and patience, doing it scene by scene at least if not shot by shot. But, you're still left with the issue of the DVNR. I suppose, with care, you could use artificial grain sparingly.

Harmy's Despecialized turned out really nice video-wise and those were similarly-treated transfers by Lowry.