How much space between the seats is enough?

Based on a study done by UK Civil Aviation Authority (CAA) a House of Lords committee issued a warning related to planes seating legroom:
“The study recommended that the regulatory minimum distance between seats should be increased to a minimum of 28.2 inches (72 cm).
The UK regulation sets the minimum distance of 26 inches (66 cm) between seats as legroom space.
The report goes on to say that “the ideal recommendation would be to increase … [the regulatory minimum distance between seats] to at least 29.4 inches (75 cm)” to include the 1st to 99th percentile range of the world population; “and, depending on the outcome of any further work to specify an optimum safe brace position, … [the regulatory minimum distance between seats] would need to increase to at least 35 inches (89 cm)”

The UK government has replied that the purpose of the research above was “to ensure that seating standards are such that passengers would be able to evacuate an aircraft quickly in the event of an emergency. There is no scientific evidence to determine a proven link between the increase in aircraft seating legroom and the promotion of health”  - read health = deep vein thrombosis (DVT).

OK - no proven relation between legroom and DVT, but what about the issue with evacuation timing? Is nobody concerned about this?

Now there is also another element of confusion in this matter: the “minimum distance between seats” is is the “legroom area/space” and not the “seat pitch” equal to the distance between a row of seats.
The trick here is that the airlines publish the seat pitch as a measure (and not the legroom space).
it’s impossible to establish the legroom space based on the seat pitch because it depends from the thickness and inclination of the seats.
Boing recommends a 32 inches (81 cm) seat pitch in economy class that is equal to 29-31 inches (74-79 cm) of legroom space, depending on the thickness and design of the seat.
This is much more than the UK regulatory of 26 inches for legroom and much more than 30-32 inches for seat pitch of majority of economy classes of European flights.
A recap here:

The outcomes of all these calculation are:
1- Current measure of legroom space in some airlines could affect evacuation in case of emergency according to the UK government. No proof that limited legroom is linked with DVT;
2- The majority of airlines is smart and provides measures of their seat pitches but not of the legroom;
3- you can use seat pitch as an approximate measure of legroom space: more is better!
4- Seat pitch varies not only by airline but also by aircraft and in same cases, the same airline aircraft could have different seats configurations (and seat pitches). Code sharing can complicate this even further!
5- Increasing legroom space of few inches/cm would mean to eliminate 1 or 2 rows of seats - it does not seem an impossible thing to do for airlines while making flyers more happy and fasten an evacuation in case of emergency;
6- while selecting a flight in economy (especially if you are tall/heavy and/or flight lasts more than 2/3 hours), consider the seat pitch as an additional criteria. You can find AVERAGE seat pitch measures for major European airlines here.

Unfortunately my own search in 3 major European airlines has proven unsuccessful in 2 cases out of 3 - no info were provided re seat pitch of different classes or aircrafts. Only marketing sentences as “enjoy lots of room…” or “the seat structure and space have been entirely redesigned for even more comfort”.