Thank you for the log.

Well, it does not look very good. If the RPM signal is really lost so often, then it can't work reliable in any way.
This event will show when signal is not present for more than 2s, which is not acceptable for any governor.
This is what Spirit sees and it can't be fixed by any software settings.

Regarding other issues - limits - this might also not present any problem at all, as described in the manual.

Receiver signal lost - this is major issue and should never happen. Spirit is reporting the problems, because they are there.
With other FBLs you might see nothing, because there is either not a log or it will not report the problem soon or the connection simply changed. Satellites are very fragile, especially the cables.
So the log should help you, not to frustrate you. This is to prevent from crashing and save your money.

Now we have to sort all the issues.

I recommend to first start with receiver part as this is the most important. But I dont believe that all the problems are common with all your helicopters.

Regarding soft stops, from 2.1 there is automatic stopping tuning. If you can't get equal stops, then it mean that it is mechanically not possible. The goal of the unit is to eliminate all side effects (e.g. bounce backs, overshoot).
When this is not perfect, general performance might be also affected.
So by fixing one thing, everything can be sorted.
To help you with tail, I will need more info - tail servo, helicopter model, your settings, tail servo arm length.
Usually unequal tail stops are due to mechanical center, servo arm length or tail limits.

If you are switching from one FBL to another, then the same mechanical settings could not work well. So if it is working perfectly on one, it might be very bad with another. On the other hand if you change it mechanically to make it work well with second one, the first one will again perform poorly. This is usual reason, why some people have good results with thing A and not with thing B, while for many others thing B is working always well.

In your case I recommend to solve the problems one by one. Never everything together and for more helicopters. For each problem it can be better to open new thread, else everything will be mixed together.

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Spirit System developer