This morning I went out and re-ran Exercise 1 with Belle using a blind cross and a front cross. Much to my surprise, today the front cross yielded the same time as the front and rear did yesterday, and the blind cross was a little itty bit faster today than the front--I think because I was very conscious of moving laterally as soon as I could after jump #4. On the downside, when I used a blind cross, both Belle and Dusty ticked the bar of the jump before the weaves--probably because of my abrupt deceleration to signal the wrap to the weaves.
I guess what I've learned from this exercise is that if you can easily do a front cross and there is not a speed sequence coming up after the cross, then a front cross is probably a better choice than a blind cross. Let me illustrate:
In the white sequence on the left, for most of us changing sides between 4 and 5 is the surest way to get the job done before the tunnel. We're not really using the cross between 4 and 5 to signal a turn--we merely need to change sides before our dog gets to the tunnel. Therefore, a blind cross is a very appropriate choice since it isn't going to slow the handler down in the middle of a fast sequence.
The black sequence on the right is similar to the one in Exercise 1 from yesterday. A turn is needed at 5. There are three options. A rear cross will work if the dog has a good switch command and dependable weave entries. However, the dog has to be ahead of you. Given how the course loops back on itself, you have to work at it to make sure your dog is ahead of you so you can get in a rear cross. On the other hand, if you know you're too late for a front cross, it is a viable alternative. (If you are too late for a front cross, attempting a blind cross instead may end up bringing down the bar at 4.)
Obviously, a blind cross will work since I managed it with two different dogs. However, a blind cross on the flat is really about speed. I had to make a conscious effort to modify my path and my speed in two places in Exercise 1. Apparently, I managed to fix my problem at the fourth jump in that exercise, but I didn't do quite as well at jump 7 since both dogs ticked the bar today.
Exercise 1 calls for an efficient, tight turn over the jump before the weaves. It was easy enough to get into position for the front cross, plus knowing I needed to do a front cross kept me from lingering longer than necessary at #4 and inadvertently cuing Belle to jump long over #5. (Even in the drawings above, you can see the effect that knowing I want to do a front cross has on my path :-) Because I have to slow down to execute the front cross, Belle is more likely to collect over #7 and achieve a tight wrap to the weaves.
If you would like to learn more about blind crosses, Daisy Peel has put together a video demonstrating three types of blind crosses, how to train them and when they are appropriate.