FSX:SE Seraphim SSTO Development Issues

Hi guys,

For the last two months I have the pleasure of working with Karl Bushby on the development of their VPACC Seraphim program.
In short it's an educational program aimed to spark and develop the interest of the young people into the space program and exploration. More about that here.
At this moment they are building a physical cockpit simulator in Ulaanbaatar, Mongolia, and I'm helping them to make an aircraft for FSX Steam Edition.
This is what we have so far:



Here are some flight videos also:

We are now switching to Linear Aerospike engines, like these on the pictures below:
linear engines.PNG

We have some problems with animation speed and effects.
First problem is with gears toggle animation, it's too fast (you can see it in the videos above). We've searched the documentation and forums and just can't find the solution.
Do you guys now how to slow down an animation in FSX?
Second problem is with engines effects. We've tried to add afterburner and smoke effects but nothing worked.
We dug trough the FA-18 files to try and copy the effects but had no luck. Tried some tutorials and mods like "How to install and edit afterburner effects" by Mark Rooks of RSDG and
"Messing About With Engine Exhaust Flame Effects In FS_X ® TWO (2)" by Mike Basford (spad007), but nothing worked.

We use 3ds max 2017 and prepar to export for FSX Steam Edition.

We would really appreciate some help with this. Hope you guys like the project!