Hi Mark,
It really does take a bit of persistance to get the hang of it - 6 months to a year should be enough to become familiar with all the basics, but you will still be learning even then! It isn't an easy thing to learn - if it was, it would never have fallen out of favour. Kind of like cycling: plenty of new-fangled looking bikes about, but you don't see many people on pennyfarthings and unicycles!
Getting the correct tension on the strop is a start - you don't want it to flop about and you don't want to give yourself muscles like Hercules by pulling it too tightly. A firm, comfortable pull is tyhe thing you need, and expect the strop to deflect a bit. You only need a light pressure on the blade - enough to keep the bevel in contact with the strop surface. Too much pressure and you will round the bevel and reduce the sharpness.
YOu should be able to tell by the noise and the look of the surface of the strop together with the 'feel' of the blade travelling over the strop whether you have got it right - the signs aren't always there, but if you are doing it right you might see the shiny surface of the strop dull down a bit immediately behind the razor, hear a difference in note between the whizz of a really sharp edge travelling over the surface of the leather compared to the softer noise of a dull edge and feel a more positive buzz through your fingers at the same time. As I said, very hard to quantify, hard to describe and not always apparent even when doing it properly.
If you have a USB microscope, or a jewellers loupe of 20x - 30x diameters it might be an idea to examine the edge of the razor in detail. You can 'roll' the very fine edge if you mess the stropping up - then the razor will need re-honing.
If the edge of the razor is only marginally dull, stropping on canvas will usually revive it. You haven't got a canvas strop if you are just using the three strops Arrowhead forwarded, but the rough side of one of the leather strops can be used in a pinch. From memory, the oiled bridle leather has the most consistent and least fibrous rough side - give the razor about 40 laps on that (one lap = up and down), followed by another 40 on the smooth side of the bridle and then 30 on the tallow-tan. Try the HHT again. Keep doing another 10 - 20 laps on the tallow-tan and testing until you can get it back to HHT - its amazing just how much simple stropping revives the blade.
A note about the HHT - its not an infallible test and even razors that do not pass it can give exceptionally good shaves. It works because the human hair is composed of lots of sclaes - something like the branch of a monkey-puzzle tree. When the razor catches against a scale it has the anchorage required to 'pop' the hair in two. The less audible the pop and the more the hair just seems to fall in half the sharper the edge. Success usually depends on holding the hair by the end and not the root - the scales lie in one direction. When hair is very dry or out of condition the scales really stand out and HHT is easily passed. In humid conditions and for well-conditioned hair, the scales lie very close to the shaft of the hair and passing HHT is less likely. So: it depends on individual hair type, how prominent the scales are and environmental conditions - that is why it is fallible! The only sure test is the shave - once you have mastered the technique of shaving.
Regards,
Neil