According to XG, this position is a (roughly) an optional double: White is technically too good, but only just.

I think I understand what is going on here. On the one hand, White has substantial gammon chances that she forfeits by doubling. On the other hand, if White fails to double, there's a chance that Blue will roll a joker and get a 'very take-able' position (e.g. with a double 3). Somehow these two considerations roughly cancel out.

What I don't understand is how one can assess these considerations quantitatively. Is there a calculation that one can do to assess whether one is too good in these and other positions?

One approach I recently became aware of is Len's Rule (also posted on this forum). However, I wasn't sure if this approach is reliable, how to apply it in this situation (how many 'taking sequences' are there?), and whether better approaches are available.

Thanks in advance for any ideas or suggestions!

If I decided to play on here, it would just be because I recognize that (1) it's a huge, obvious pass, (2) I have good gammon chances due to Blue's blot in the outfield, and (3) it takes a joker from Blue to get a clear take next roll.

But of course this might not be that useful because how influential the factors are is a matter of degree, and it just comes down to a judgement call like a lot of cube actions. The more positions you see (and screw up on), the better your judgement will become. I've never bothered with any formulas except in races/bearoffs.