@Kozushi I don't want to go offtopic here, but...
The book tells you to do 2H-Swings until you own the movement (the hinge) and then switch to 1H-swings. You do that when you start with S&S, so for almost anyone that means swinging the 16, 20 or 24.
You don't hit the time standard with the 16 using 2H-swings, then go to the 24 with 2H-swings, then the 32 etc. (what I can tell by your posts is what you've been doing).
If you're not ready to do 1H-swings you have no business swinging the 40.
You stay with 2h-swinging the 16 until you really own that movement and then work in sets of 1H-swings with the 16. Once all your sets with the 16 are 1H-swings you start to work on the time standard and then increasing the weight.
After that, except for the ocassional 2H-swing session to maybe spice things up a bit, you stay with 1H-swings completely.
The GS in the warm-up is a mobility drill. You stay in the bottom position and move around (prying). That should be relatively easy and should last a bit, so you use a light bell (12, 16, 20 maybe 24 if you're really strong).
Using the 40 you turn the GS into a strength move and that's not what's the role of the GS in S&S.
Prove me wrong, but I highly doubt that you can stay in the bottom position, pry around and staying relaxed (including relaxed breathing) for 30-60sec while holding onto the bulldog.