Tartan doublet DIY notes and details.

[fluter]

Did you use any shoulder pads in your jacket construction? Sleeve cap?
What type of interfacing/interlining did you use? Any hair canvas?

I have not done so, but I'd say "yes" to all.

Here's a very accessible book that describes 3 levels of construction (fusible interfacing, machine sewing, hand sewing). Tailoring: The Classic Guide to Sewing the Perfect Jacket