It's commonly believed that BC7 has this incredibly large search space (which it does) and is slow to encode, but only a few mode combinations and encoder search settings are actually valuable (i.e. highest quality for a given amount of encoding time). The valuable codec settings appear to fall into these four major regions (three if you ignore the last impractically slow region):
Note the max practical PSNR for this test corpus is ~51.39 dB RGB avg. PSNR. For reference, BC1 non-perceptual is around 10 dB lower than BC7 on average, so even real time BC7 is massively better than BC1's quality.
Region 1: Real time
In this region, you only use mode 6 (which will have noticeable block artifacts), or you combine modes 0 and 6 but you limit the # of mode 0 partitions examined by your partition estimator to only a small amount, like 1-4. Only a single partition (the best one returned by the estimator) is evaluated.
You can increase the # of partitions examined in mode 0 to improve quality a little more, which will reduce or eliminate block artifacts. You must handle pbits correctly (as I've detailed in previous posts) to exploit this mode combination, otherwise mode 0 will be useless due to massive banding.
Encoding time: .5-3.5 secs, average quality: 48.2-49.09 dB RGB PSNR
Region 2: Fast
Encoding time: 5.5-16.4 secs, average quality: 49.8-50.8 dB RGB PSNR
Region 3: Basic
Encoding time: 21-54.0 secs, average quality: 50.98-51.24 dB RGB PSNR
Region 4: Slow to Exhaustive
Encoding time: 132.8-401.97 secs, average quality: 51.36-51.39 dB RGB PSNR