chh wrote:I'd think there would have to be a pretty good reason as to why you are using the directional in the first place and just making it easier to get on rope I don't think necessarily counts.
Making it easier to get on and - more importantly - easier to get back up over the edge is the best possible reason for a high directional. Edge trauma is messy and dangerous, and navigating the lip on ascent can be difficult and ugly.
Now, if you were making the back tie with additional materials (other than the rope) and had a prussik progress capture system I wonder if you couldnt just extend the "backup" anchor closer to the drop with all of that stuff or explore some other option.
You could, but long anchors tend to be messy, may involve rub points and mud, and even with webbing add some stretch to the system.
I use 8mm cord for back-ties (since there are 3 strands to share the load) and webbing for Wrap-3-Pull-2 anchors, which offer strength, cinching, and allow direction changes better than almost any other anchor system. Carrying some webbing and 8mm cord to the pitch head is usually easier than carrying extra 11mm rope.
Now, if you were WAY back there and it was impossible to make a straight line with the line connecting the primary anchor and the back-tie...
If you can't find an in-line secondary anchor, then it's sometimes possible to vector two back-ties to create a focused or floating anchor point where it's needed. Taking a little extra time and effort to build the primary anchor for entering and leaving a pit doesn't seem to me to be excessive, since that's your lifeline back to the world and may see 2-person loads if a pick-off is needed when the party is exhausted on ascent.
It is possible that I'm still not picturing your back tie well enough though
I've tried several times to upload an image without success, even though my files meet the requirements of PostImage.org