Lined leather belt - DIY

[rendoman]

Hi all!
As a small gift for Xmas I decided to build a belt for my girlfriend.
I used very good cowhide for internal and external layer, the interior is pressed leather.
The belt is 22mm wide, buckle is harp shape, pretty heavy. Waxed twine as usual.
It's the first time I use a water color for edges, to be honest I think I have to try the burnishing tool and maybe an hot blade, since the results isn't so good.
Any advice in order to improve aesthetic result?

As usual a ton of pictures