All spindles are forged steel so I think it would be ok the nature of the metal is bending rather then breaking so if it bent you would pick it up during a wheel alignment or notice uneven tyre wear.
It depends on what you are doing to it. Your question was pretty broad. Why would you put lightweight spindles up front ? You would want the biggest bearings you could get unless this is not a street car. More info ?? in either case you want the biggest brakes you can get on the front especially if this is not a street car. No brakes at high speed is not fun.
Hi Leo,...It's left over set up from my Bblock 'cuda strip days running the lightweight Strange single puck aluminum brakes that would only fit the small 9 inch drum spindle. I wondered about them every time the front settled down after launch. I don't know to keep them on with better bigger calipers for primary street cruise duty now or what.