I suggest that you read this -
http://www.fm-base.co.uk/forum/shar...s/365798-most-efficient-way-test-tactics.html; in that thread, TFF explains many things about tactics testing, also, he shows how accurate any tactic testing can be and how many matches you need to test in order to find out "accurate" score for a tactic
You can browse through out this thread and find results for many different tactics, I'd say those results can't be consider as "the final verdict" because TFF explained and showed that only 1 test (170 matches) isn't enough but it still gives good representation tactics' quality.
The best tactics for FM17 can reach 340 points and +150 G.D. in TFF's tactic testing league