All the niff-naff mentioned in the first paragraph in the above post that you end up getting dumped on your table sums up where the rest of the week goes.
18-20 hours a week is a limit unless you do not want to end up with stale materiel that is not updated based on recent exam feed back.
The attitude that somehow you are guilty of time theft unless you are spending 37.5 hours a week in a classroom seems to stem from clueless types in management who have never had to spend time in front of a whiteboard and explain a subject in great depth. Anyone can spout forth very clever ideas lacking in practical detail and pretend they are a management genius - but how many ever have any form of management training ? An MBA, for example.
1-2-1 for those who request it alone can easily add another 5-8 hours a week to the workload. Plus there is extras you end up doing - semi cadet welfare, scheduling, future planning, updating records, student reports.
18 hours a week gives near enough 900 hours a year and just like pilots, just because they are not flying does not mean they are not working !
I don't think the ex forces back seater is the only suitable source of TKIs. An experience GA Flying Instructor, flight crew grounded for medical reasons, or someone who has in fact taken the JAR/ EASA exams they are actually teaching and is sufficiently enthusiastic is just as suitable, and probably less likely to have the younger generation of trainees suffering from a glazed over expression as some of the more stale war stories are trotted out again !