[81turbota]

I'd grind the spindle. I wouldn't want to compromise the tubular A arms. Tubes are very strong until you introduce a stress riser such as a kink, dent, deep scratch or thin spot. The cast iron spindle wouldn't be compromised if you removed some material from that location.

Correction - that's a factory stamped A arm. I'd still grind the spindle. The rolled portion of the A arm contributes to its rigidity.

You're not wrong. The suspension and steering should not bind and fully articulate through its range of travel.