1. I don't like the idea of adjusting the clutch by comparing it to a non-related reference but in this case, it seems to work out ok.
2. That's a little disturbing. There might be a manufacturing defect in the new slave cyl. Now that you know how easy the swap actually is, I suggest going back to stock and compare. Remember, the whole purpose of this swap is to gain feedback from the clutch at the expense of pedal force.
On the subject of verifying clutch adjustment, here is yet another way to get comfortable with the tough/grab point.
Find a nice flat place where you can creep along at a casual walking pace, say 2 mph.
1. Get going in first and disengage the clutch.
2. Adjust your speed to coast at 2-3 mph.
3. Without giving any gas, slowly raise the clutch pedal.
You will feel the characteristic
clunk of the driveline backlash when you reach the touch point.
What is happening here?
With the transmission in gear, the wheels are spinning the clutch disk.
The engine is idling a little faster than the clutch disk.
When the clutch begins to grab, it accelerates the clutch disk and all that transmission and differential backlash is taken up in the clunk.
You can tickle the clutch at that spot and get a feel for the exact touch point. Is it high enough that you know you can comfortably disengage the clutch for each shift? That's basically what you need to decide for yourself. Mine's maybe 1.5 inches off of the floor. I have long legs and I always mash it to the hardstop when I shift.
Any time you mess with the adjustment, always always always verify
this.