Leather Edge On Canvas Tool Roll?

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I've not done a folded leather edge trim before to finish off the edges of a canvas tool roll. I've tried some sheep leather, it's turned nicely round the corners of the tool roll but I've had to cut 4 pieces! The multiple joins don't look good though.

What do you use for this type of finish, do you cut ever decreasing circles from the sheep hide or is there a cheaper alternative out there already cut for this job. I've been googling but mainly come up with bias binding and very expensive "per metre" faux leather which also isn't wide enough for what I need, 25-30mm.

I'd thought about using the canvas, cutting strips to edge it but it's a twill and frays and too thick to fold over (maybe?)

Thanks all