Hi Ian,
I understand your point regarding the edges clearly - true indeed. And thanks for that splendid Russian link you've just included - it has provided much much closeup shots on the T-34s and other Russian AFVs that's quite lacking on the internet these days. Would help me detail my hex-turreted T-34, KVs, JS-2/3s, and all modern types.
Mark, to use a loose analogy - just imaging placing a cloth over a table. The hanging edges towards the bottom should produce a straight down edge, instead of curving towards the insides. That's how I envisioned this version of the (actual) T-34 turret to be.
Cheers,
Lawrence