You will not find anything in your TX that will give you the degrees in which your blades are at ...

The only thing the curves ( or y-axis ) tells you is the servo command that will be transmitted when the stick is in that position. Since you can install a servo arm in numerous positions and have variable length control links ... it is up to you to set up the heli to make the TX numbers make sense ... ie set the Y-axis at 50%, set the heli/servo up to be centered, etc.

Bottom line is, your TX has no idea what it's transmitting to or what it's doing. It is up to you to make the heli and TX work together.

For example, you could set the low stick (pos 1) Y-axis to cause the low pitch to be -3° in normal mode by dialling in the numbers to achieve the desired pitch ... read from the pitch gage you are using. Then in idle up, you could set pos-1 to achieve -8° pitch just by changing the numbers.

"The position on the pitch curve is meaningless unless I know what the end point values are."
Again, if you are trying to make some meaningful connection between your TX settings to get a meaningful pitch angle, don't bother. It won't happen. The only meaningful thing you can read is the pitch gage attached to your main rotor.

"Where do I find this information? Does it have anything to do with servo endpoints?"
100% on the curves equal 100% of the ATV settings. ATV settings are the limits of the servo movement. Typically, most people shoot for 100% ATVs. So if you dial in 50% ATVs then 100% curve settings would be 100% of the ATV setting.

Where do you find the degrees in which your rotor blades are at? On the pitch gage attached to the rotor blade. You do have a pitch gage don't you? Again there is no magic TX menu that will tell you that your rotor blades are at hover pitch. The TX will only tell you what the command to that channel/servo is. It's up to you to make it meaningful at the heli end.