The fps thing might happen because overlay panels and undocked 2D ones might interfere with the antialiasing setting of your graphic card. This is a general issue, not a special Civa INS one.
If you use a Nvidia card, try "override" instead of "enhance" in the AA policy. This can be done via the great Nvidia Inspector. Just google the phrase and you will find the downloads and guides. It's freeware.
ATI cards surely have AA triggers too and I have to state clearly that the Civa won't affect fps by design in any way so there surely is something else causing this.


As for the guidance stuff, you should make sure to have all switches set up correctly. INS aligned, Nav mode active, Nav mode switch (if using my modification) and the INS/Doppler switch on the 707 should be mentioned there.
The next thing will be the AP and FD setting. So there are some sources for "no guidance" of course.


I wouldn't blame Captain Sim for INS problems at all. This is an addon module and it works fine. We can't really rule out some more or less big error on your system or setup causing this, so the refund wish lacks a bit of an objective viewpoint in my eyes.
They mainly deliver a complete aircraft with the Doppler system. The INS is an addition (which works) but isn't necessary to drive the thing.
If I could read more complains about it, we might come to a point where CS would be to blame, but if the setup is done correctly, this additional gauge drives your AP, adds some useful data and doesn't affect the performance at all.
I know it can be unsatisfying to read this but, as I pointed out above, there are quite some settings to get mixed up. Maybe you're a victim of at least one of them and as long as the input stays diffuse, help will be somehow catchy.


I also wonder about your reports which can't be reproduced here. My modification can not for example cause any problem with the landing gear showing or not. I can't, because the gauges there aren't connected to such things in any way.
I hope you don't feel offended if I use the example of someone telling my that he pulled the plug of his monitor and now his fridge isn't working anymore. But that's pretty much my impression about some things there.

Let me assure you that I have tested my small Civa integration and I think some other guys did too (as they are using it or used it as a start point).
As we are all humans, problems and mistakes surely can arise but I can't see any of this in the tutorial and the only non-working reports so far were caused by faulty editing the stuff, which is a human factor too, no problem with that of course.

So maybe a short break from all 707 stuff will lead to a fresh minded approach after some days or so. 1.2 is working, with and without Civa INS.
One has to make sure that no other software with e. g. guidance control interferes it and as we all use our sim with loads of addons, this can sometimes be hard to oversee.