If you want to go the FREE route, you hold the advantage here as you own the actual RealLife aircraft.
Supply the Photos suitable for creating a Colorscheme _CS.rfx:
Top View, Side View, Bottom View any additional Details for the included Decals and such.
Many eager colorscheme artists available here to help you out on that.
Supply the dimensions and weights of your aircraft Variant _AV.rfx:
Weight of Wing, Fuselage, any Landing gears, weight of Elevator, Rudder.
Dimensions of all of the above.
Which Engine you are using including Prop.
You can edit these parameters in the Aircraft Editor in Sim, or someone else can do that for you.
You can follow along with the sticky on creating your own physics variant.
Unless you want to spend $80 for the upgrade to 5.5 Plus an additional $30 for the expansion Pack. it's your choice.
Have Fun!