Front tires

I need to rebuild my 1973 440 Duster front suspension and replace the front tires. I just bought the car so I can only speak for what I can see on the car. The current tires are 205/60/R15, and are badly worn on the outside edges, down to the steel belts. The rear tires are 255/60/15.

Obviously I have suspension/alignment issues. I noticed in some test driving that the car likes to follow changes in the contour of the road. It will pull strongly at 40-45 mph in the direction of dips in the road. I need to replace the tires and I am considering using 50 aspect ratio instead of 60. My reasoning is two fold, the 50's will lower the front of the car another 3/4". The car does need to be lowered a bit now and I will lower the rear end as well prior to alignment. The 50 aspect will also strengthen the sidewall from flex. With all things being equal, good alignment and suspension rebuild, will the stronger sidewall (50 aspect) keep the car from pulling better than the 60 aspect sidewall?

I know I need alignment etc, but I need to set car height first and have tires I can drive to the shop with to get the alignment set. For that reason, I need to make a tire choice first as it affects height of the car.