Ey-up Fozzer old pal.......from my massive archive of "stolen" tips which I have "acquired" , I came across this one which seems to fit your bill......totally untried by me but you know how to backup stuff by now so why not give it a whirl....
To accurately place the objects you need to slow down your slew speed. By changing the following lines in the FS9.cfg file you can do this.
[SLEW]
MaxLateralRate=1000
MaxVerticalRate=1000
MaxPitchRate=1000
MaxBankRate=1000
MaxHeadingRate=100
Hope this helps.....commoner

Comm, my old Chum....!
You are the light of my life, as always!...

...!
Like you, I had all my favourite FS9 settings and tips in my FS 9 Folder, but having to do a complete re-install involving a delete of my original FS9 Folder, (don't ask), I lost the bleedin' lot!....

...!
Your tip reinstalled part of my memory again, and the result is here:
Involving a couple of "slashes", (like we incontinent Oldies are used to...

...), to save the original data...

...!
[SLEW]
MaxLateralRate=1000 //40000.000000
MaxVerticalRate=1000 //1000.000000
MaxPitchRate=1000 //360.000000
MaxBankRate=1000 //360.000000
MaxHeadingRate=100 //360.000000
Thanks Comm...

...!
Cured the problem, everything is now slowed (slown?) down to my usual Snail speed now...Joy!...

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Paul...

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.