Not sure how tall the picket fence is but I assume that you know that good ole Limelight can easily swallow a picket fence if you do not distance it far enough? It can get 8-10' high but it looks gorgeous in a hedge!

I have always equally liked Limelight, PW, Pink Diamond and Quick Fire. Limelights in a hedge are show stoppers for me. QF blooms earlier. PW may flop a little when the flowers open up since they are so big. Aged PD blooms look great.

I don't grow Limelight, but I prefer Quickfire to Pinky Winky. QF starts blooming earlier by several weeks, I like the form of QF's panicles better, and QF develops a more appealing color as it ages IMO.

I have a rather large yard so I have one of each. Heh. As for a hedge, Limelight would require the most maintenance. You could toss in a few hibiscus syriacus too (if hardy enough for 5a) as they come in many colors, self seed (start with a few) and grow quickly.