Re the Lift Method: Both Philip's and Skippy's understanding of it is correct.
As they've already said, when an SSG shot is used for the lift method (whatever weight is used it should just be enough to sink the float) the fish does not feel anything like the full resistance of it, for it isn’t lifting the full weight. Most of the weight has been taken up by the float.
What you do is fish overdepth, the deeper the water the more overdepth you fish so that the angle from shot to float is right. A rough rule of thumb is a foot overdepth for every 3 - 4ft of water.
The sequence is this, when you cast in the float is lying flat (due to being overdepth), then you lay the rod on two rests and gently (so as not to disturb that bottom shot) draw back until the float is almost submerged. The shot will now be on the point of moving. So when that shot is disturbed by a fish it is only feeling what little is needed to break the balance and the float rises. Hence using two rests to eliminate rod movements that will disturb the shot.
That all works out OK until you have a heavy drag on the water, so when that happens the balance between shot and float has to be tipped in favour of holding bottom. The lift method still works but is not anywhere near as sensitive as when used on a calm water.
Your description of how to fish the lift method is spot on. So often the need for a float that just sinks under the influence of the shot is forgotten, and in many diagrams the rig is set at exact depth, which is theoretically possible, but rarely practicable.
However, I don't agree with your statement that 'most of the weight is carried by the float'. In fact, if the fish actually lifts the shot from the bottom (as opposed to merely dislodging it) it carries an ever-increasing amount of weight the further the float rises, and by the time it topples over the fish is carrying almost all of it. I think the reason the lift method is at all sensitive is not because the float carries the weight, but because it tensions the line to a point where the shot is almost moved (as you quite rightly describe). I don't think a fish lifts the shot very often anyway; it simply dislodges it and tension does the rest. However, shy biting fish will often detect the large shot, and do no more than cause the float to rise a fraction before they drop the bait; you might hit them if you're quick, but most times they've gone before you can react.
Nevertheless, there are ways of increasing the sensitivity whilst retaining the lift method principle. I for one wouldn't fish lift-style for roach or crucians with a one-swanshot lift rig. The trick is to use a fine stemmed antenna float with a body at the bottom. This carries maybe 95% of the float's shot loading, and at no time should this weight be allowed to touch bottom. You can put it around the float in conventional waggler style, but in practice it's more stable if you place it somewhere between mid-depth and about a foot off bottom.
The final shot (a small one) should be of a size that, combined with the aforementioned bulk shot, just sinks the float. The smaller this shot, the more sensitive the rig, but the shot must sink the float completely. It is placed two to six inches from the hook, and should be allowed to rest on bottom, with the float set overdepth (remember the bulk shot should always be off-bottom). Now, when you tighten up, you draw the antenna down in the water. Obviously, the less buoyant the antenna part of the float, the smaller this shot can be, but don't fall into the trap of thinking a shorter antenna will work as well as a thinner one; the float proportions should be such that the antenna comprises at least half the total length.
The rig works very well. If a fish merely dislodges the small telltale shot, the float rises a little. If it picks up the shot (which it's more likely to do without taking alarm, seeing as it's so small), the whole antenna rises out of the water. At no time does the fish lift the bulk shot to do this; only the telltale is involved. If it moves off with the bait, the float sinks, not because the fish has pulled it under but because the weight of the shot has dragged it under, and because the float sinks before the line is pulled tight between hook and float, the fish feels no drag from the float's inertia.
If wind or drag causes the shot to keep shifting, simply go further overdepth, increasing the distance between telltale shot and bulk accordingly, but keeping the float-to-bulk shot and telltale-to-hook distances the same. This makes the angle between lake bed and line from talltale to bulk shallower, reducing the tendency for the telltale shot to trip along the bottom.
It sound very complicated, but actually it's the simplest thing imaginable. If I can get around to posting a couple of illustrations, which I fancy would clarify things enormously, I will.