anybody use lead additive to gas?

[vhalstead@linkline.com]

Hi List,
I have a 1974 TR6. When leaded gas was phased out, I used to put in a lead
additve every couple of gas tanks. My car was in restoration, and now I am
back to driving it. I used to get the lead additive in a bottle at the
UNION 76 gas station. Here's my question:

1. What is experience/opinion about the lead additives?

2. Any brand preference?

3. Advice about frequency of adding to a full gas tank?

Thanks for any feedback on this.

Virginia
1974 TR6
Los Angeles