@jmorth, what a stunning "living fence" you had! Love it!
I grew Russian Giant sunflowers for the first time last year, and I never saw a goldfinch on them, nor did they do any damage to the plants. I have a flock of goldfinch here all year, and they didn't touch that one. Maybe because it is the striped variety. That plant was giant, and lived up to its name! We have wind here almost constantly, and I didn't have to stake it, which was great! I will be growing many more this year! Last year was just to see if they would do well, and they did. I'll be adding many other varieties this year, and I can't wait to get started!