For VHF, for max range, higher is better.
Question is, is it worth the hassle to get that extra range? Telescoping extender has drawbacks: What to do with the extra cable while it's not extended, stowing/dispensing, etc.
Someone on this site mentioned having a short whip (3'?) that was mounted near the top of the A-frame, which when folded down was flipped 180 degrees, so it paralleled the frame tube. Sounds like it would be well out of the way like that.