I do it the same way as you do and got very good results, maybe things changed with endpoints on 2.1.0 as it's more self adjusting?
Beside self adjustment functionality I believe a good initial setup helps anyway to get better end result.

1) Set mechanical center the way, tail is holding without to much interaction of Spirit, with 3-4 Degrees against boom pending on rotation direction. No Trim on Rudder Channel, just mechanical. (In early days this was done with Tail Gyro in Normal Mode not Heading Hold mode and adjusting push rod length, till tail was self holding)

2) Than I set mechanical Limits more or less equal to smaller one and reduce by 3 points to avoid binding and not going beyond 45° of blade angle. If real limits are 125-136 I go for 122-122.

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Oxy4max SpiritPro + HW // SOXOS 550, SpiritPro, HW120A V4, 920KV // SOXOS 600, SpiritPro, HW160A, Pyro650 // SOXOS Strike7, SpiritPro, HW160A, Pyro750 // Skywing Spirit Aero // FrSky Horus X10S + Taranis X7 /

So there is nothing wrong with my method?
If I would go for equal values like you the pitch would not be the same left and right..
That is bad for the stopping isnt it?

Good question, in my case its the same pitch on both sides out of center position. My Soxos have a tourque concept on rudder control with little mechanical parts.
Well if you need to do trimming in spirit on rudder channel 4 to get servo centered it also influances limit values.
In this case (on my trex 450) I went for equal mechanical pitches out of center poitions. But make sure in center poition (3-4°) all is at its best 90° position to get equal servo angles on equal pitches.

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Oxy4max SpiritPro + HW // SOXOS 550, SpiritPro, HW120A V4, 920KV // SOXOS 600, SpiritPro, HW160A, Pyro650 // SOXOS Strike7, SpiritPro, HW160A, Pyro750 // Skywing Spirit Aero // FrSky Horus X10S + Taranis X7 /

Method described by Adrian is good.
You can also use Normal (Rate) mode with the Spirit unit just by going to a negative gyro gain (when Stabi/Function is set to Disabled).
In this mode you can set mechanical center position exactly.

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Spirit System developer

I made some photos to show you my tail.

Zeroposition:
In Spirit i have 0 Subtrim on CH4

Right limit:
43mm, so with 50mm blades: sin^-1(21,5/50)x2 = 50,9°

Left limit:
55m, sin^-1(27,5/50)x2 = 66,7°

The angles are different, i set the maximum so that the tail pitch slider doesn't have contact on the left or right limit. On both sides as far as I can go without a contact, but why are the angles so different?

Limits in Spirit are both 112...

And for bad stopes after pirouetting counterclockwise is the right limit to small or the left to big?

Thank you for the details!

Both limits are too high. Normally it is enough when both angles are approx. 30°. If it is that much as in your case, it will cause troubles (with stopping) or during excess load.
Normally left limit is more important, because of torque from main rotor.

So I recommend to decrease both limits in the same proportion first.

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Spirit System developer

Max 45° would equal to: √(50*50/2)=35mm distance on blade tip. I'm very interested on your feedback on tomas sugestion only to go for 30°. I did find out myself to agressive angles are causing air flow demolition, sounds also very strange on full pitch and you see the tail blades at full angle having limited effect on holding.

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Oxy4max SpiritPro + HW // SOXOS 550, SpiritPro, HW120A V4, 920KV // SOXOS 600, SpiritPro, HW160A, Pyro650 // SOXOS Strike7, SpiritPro, HW160A, Pyro750 // Skywing Spirit Aero // FrSky Horus X10S + Taranis X7 /

30° is angle between blades (so pitch angle of one blade is 15°) or pitch angle of one blade (so angle between blade is 60°)?

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TDF, TDR, Logo 600SX, Oxy 4 Max @ 3Digi, VBar Neo, Spirit, Grapuner mz-32, mx-20

Good point thanks, I guess 30° on each side meaning 60° in between the blades. In this case Scout is not really off to bad with 51° and 66°, maybe on high side with 66°.
The initial question was where does the difference coming from, the difference should be 2 times the initial difference of 3° eq 6°, the rest is coming out of the mechanics, if things are not really 90° and if you had to use Subtrim on rudder to get the 90° at the servo horn, this is also influencing the travel itself.

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Oxy4max SpiritPro + HW // SOXOS 550, SpiritPro, HW120A V4, 920KV // SOXOS 600, SpiritPro, HW160A, Pyro650 // SOXOS Strike7, SpiritPro, HW160A, Pyro750 // Skywing Spirit Aero // FrSky Horus X10S + Taranis X7 /

I'm going to try 45 deg this weekend then we will see if this was the problem.