Lpjs wrote:As for tension -- I keep reading that tension should be firm, but light. I'm having a bit of trouble determining exactly what that means, though. I think I may need to find an expert (in person) that can show me what that feels like.
Surely it'd help, though many of us didn't have the luck to meet somebody to teach us in person, yet achieved valid results.
A personal thought of mine is that at first, while confronting a physically tough, big bad lock, we think that X tension is valid if not too little for manipulating such a strong chunk of metal. Yet you'll later find out that if the mechanism works fine, an infinitely smaller tension is enough and anything more than that is an obstacle to feeling and setting pins correctly.
I also understand the problem of too much, too little being far from scientifical. We've all been there. Measuring your tensor length, putting a dent on its end to hang a small weight and work with the lock flat to the ground would make a scientifical method to measure torque, since
Momentum = Force x arm and this would give you a number to look after and a modern approach, though such torque would vary from lock to lock. I've never bothered with measuring necessary torque to manipulate locks, though if you ask me an eye-estimation, I'd say 20 grams applied at the end of a 6 cm tensor, thus 0.001 Nm torque.
Lpjs wrote:For raking - I've been using what was described to me as a "standard rake" (the squiggly line)... Think I'd have better luck with a half diamond?
That squiggly line you're referring to should be a bogota rake

It is a more complex raking pick than the half diamond, and due to its design it may be tickling more than 1 pin at the same time (or again they're just stuck with too much tension). I'd suggest trying the half diamond, not just because I think it is one of the most versatile picks, but also because it gives you more selective control and you can easily make one yourself.