Yeah, CharlesSpencer, there was a nice heap of BB songs coming from you lately! That’s very cool!
Just jumping in to show you that I personally respect your efforts, and I am sure if David had any free time, he would do that officially for all the Singular Sound as well! 
As far as your suggestion goes, yeah, I was definitely running into the same issues you are running as well. If you bother to check my video once again, you can actually see, that right before I play the last solo, I’ve originally wanted to transition to the second part, but I’ve failed to hold the pedal, tapping it instead. I’ve actually panicked! I knew I was f…ed in that there is currently no way to undo a fill into transition… (I was filming my video “as is” without relying to any post-processing) But the fun thing is that I loved the result better!
So, staying on topic, I can tell you that there is a special parameter in the BeatBuddy called Queue Period. It is a percentage-based value basing on the bar length, that sets instant-queued breakpoint. More info can be found here - http://mybeatbuddy.com/forum/viewtopic.php?f=11&t=51&p=157#p157. TLDR: If pressed/held before Queue Period (of let’s say its default value of 50% - in the first half a bar), you’ll get the fill kicked in instantly. Pressing/holding after this value (in the second half a bar in this example) will queue the fill to start when the next bar starts.