My advise take a good Bf 109 Gustav Template and go for it, I have chosen the G-14. But I recommend you to built up yourself.
I built mine from 3 existing templates (my customized Cannon Templ to fit with Revolvers Lighting and Blending Effects), as to get a clue which parts are different just take a good working skin. Go to Simmers Paintshop or M4T, a lot of Templates lurking around, as well as good Mechanical Layers as Add-ons.
Get yourself some pics/data of real Avias, to build up the Mechanic Layers/Stenciling.
A Tipp to make the Propeller hub look better, define a slightly larger area, most Skins are too narrow, with Blisters between Hub and engine nose. What most Skins also lacks, are the S-199 typical Engine-Cowling vents, Canopy section, they differ from your Template/Bf 109 whatever. There is more to explore though, it's what I remember. A did a Pack of Skins for my private needs a year ago. The more you research the better the result, it's mostly fine details, but they make it look proper at the end.
Hope it helps