No heat, just bend slowly.
Take them apart if you have the patience (TGR thread) but it's easier just to clamp the brake pad closed in a banch vice with blocks of wood each side, bend both arms out simultaneously then rebend. Or even just mount them as-is, snap a boot in, bend out, then rebend.
Ski pole sections for bending them out, then hold with vice grips and rebend with a small box wrench. When bending them out, 45 degrees is fine, then rebend another 45 a little further down.
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