If you just place/piggyback a 3xRig on the end of a 5xRig you have 15x. If you inset the 3xRig, so that it pulls on tail of 5xRig with it's 3xPosition, but then also the 2xPosition of the 3xRig(usually put on anchor) pulls again on the 5x, you can get 21xEffort + 15xBodyWeight (of BodyWeight used as input into the system). i think we must all ways and always break it down to device weight and device power (even of yourself) as separate considerations in these things, for the static weight will have 1 pull/push, whereas produced power of same device will have it's force and it's equal/opposite. If you inset your effort(s) inside of the 3xRig that in turn is inset inside the 5xRig, you get 32xEffort + 21xBodyWeight. That 32x comes from the series of insetting/stacked multipliers, the 21x not as much, as it carries lower multipliers, and the originating pull(s) have the Bodyweight + Effort + equal/oppsoite of Effort... All you have to do is place the 3xRig to pull at potent points, in opposite directions on the 5xRig.
MTL: Ancient Ship Rig, shows an ol'example.
Usually, we just look at placing a pulley on 1 of 3 positions:
2:1-On the load to give 2xPower, that requires 2xDistance input.
1:1-On the Anchor position as a 1:1 redirect, no alteration in power or distance, just change in direction.
1:2-Or, on the effort input, for .5xPower, but at double speed.
So, an anchor position is usually looked at as no power gain. But, because of the promise of the equal and opposite reaction/force; we can use the change in direction of the anchored pulley to capture the equal and opposite (direction) force, and align it back around to pull on load, for 2x power from an anchor position. Because this takes an open system, and makes it a closed one, so it conserves more of the forces, and folds them to target, rather than terminating their flow at anchor.
Also, insetting a system (or effort as above) inside of another system (so that it pulls 2x on that system) can give more multiplier; like in a Spanish Burton etc.
Another reason to place a lot of force on tree, is that the hinge strength is set by the force on the hinge at first folding. So, if we increase this force at the point of first folding, we can get a stronger hinge for better steering and softer felling. Notice, that if the tree will then fold on it's own the rest of the way Naturally, pulls added after first folding event, would only serve to hasten fall/ for a harder fall. A softer fall can mean less ground damage, spring poles etc. But, do remember that you give up distance, stretch, forces to friction etc. So, at some point this is just a theoretical discussion; which too is important, just to extend the limits of what you can do, to give more immediate survey of workable strategies.
So, with a 5xRig alone, we can get 8xEffort + 5xBodyWeight, with this 2ndHand/underhand technique. But, we don't all ways have to; so we can pull faster at 5xEffort as far as we can, but then drop gear to 8xEffort(but slower pulling/ more distance to input per output) by using equal and opposite pull of free hand pulling on system too, to finish; so this can be a transmission of sorts. Also, a prussick, can be tended; this will allow a pull to be placed on system, then held automatically by system to take break/conserve forces, set up for impact, leverage with perpendicular force(higher multiplier) etc.
These theories can also get your truck unstuck, help to tie down, bind etc. We probably won't take them as far there, but just immediately know more fully how to immediately, and sometimes seemingly magically maximize, by calling up these forces correctly, for as Sir Francis Bacon gave us..........
