You will hear a lot of "interpretations" of the so called CF/TF ratio, some use TF/CF ratios etcetera...
Just follow Majestic itself at
https://blog.majestic.com/research/...rust-flow-as-an-indicator-of-profile-quality/
The CF/TF ratio is the one, that should be used and it should be <1.8, which is the median of all Majestic million websites, they have checked.
This
CF/TF ratio or Trust ratio is just to quickly filter out domains!
Now coming back to TF:
TF > 10 is ok, better TF > 15 and for great results a TF of 20.
Referring domains should not be lower than 10, but also look for referring IPs and referring subnets to be sure, backlinks are not coming out from like "link farms" from the
same data centre.
Most important!
Hand check all anchors for SPAM, all backlinks at ahrefs and majestic for quality and authority and the domain history at archive*org to assure, the domain was not used as link farm or PBN or/and was spammed.
Hope, that's helps?
Cheers
Dan Kappenberg