The way the profiles are set up now, "Let McAfee decide" is your closest match to having both Read & Write scan enabled.
It is also the best practice option of the available 3 (or 4 in the case of the Low Risk tab).
The "Let McAfee decide" takes advantage of scan avoidance logic inherent with the AMCore technology. It scans files that need to be scanned (based on our determination).
When choosing between Write or Read options, only the Read option provides security. So let that be the decision point in how you assign processes to a particular profile -
To better understand why only Read scanning provides security, check out my blog: On Access Scanner: Write Scan - It doesn't work like that.
Remember though, "Let McAfee decide" will be the best option to pick as it provides best security & best performance for most environments.
I am not sure wether I like this or not but I guess there where more than just one test for verifiying the new behaviour is at good as the old one in comparison. At least: I hope so. Are there some more technical documents with which the configuration or the behaviour of the "Let McAfee Decide" Option are described? I really have to admit: I am feeling uncomftable with not knowing how McAfee decide what and when to do...but thanks for the Answer of course :-)
I've just now published a new document to the ENS 10.1 page: Explanation of AMCore Trust Model v1p3.pdf
Hopefully this will suffice for explanation of Scan Avoidance (because it seems unlikely we'll release something with more specifics, but, we'll see).