I had no idea about the quick speed burst! That actually did help. I couldn't get targets to lock (I even checked my key mapping; I was using the right [re-mapped-by-me-earlier] key). But eventually, after walking away for most of the day and figuring out that speed burst, I got it.
Cheers.

I don't think I'll ever prefer dragon form (more's the pity; I've just seen the geography of Orobas Fjords...) but at least I got my tower!