So we went to the doctor on Monday and got another peek at Mason and Owen. They couldn't find the heartbeats very well with external fetal monitors (the babies were moving around quite a bit) so the doctor went ahead and did the 28-week ultrasound.
Everything still looks healthy with them, which is good. They weigh 2 lb 3 oz and 2 lb 11 oz (est) respectively, which is in the 20th percentile, which is right on target for twins.
They have changed positions from the previous vertex-vertex positioning to breach & transverse, which means that baby A is breach (feet-down) and baby B is across Erin sideways. If they were delivered today, that would mean an automatic C-section. Supposedly 32 weeks is when the babies start to move into position, though, so as long as there's still some room they may move themselves back into the right position.
We were supposed to do the 3D-4D ultrasound also, but when we tried we couldn't get any good pictures of their faces, which is really the interesting part (everyone knows what a foot looks like). We'll try it again on a future ultrasound and if we get some good video then I'll post it on here.
Oh, also, Erin's now measuring like she's 40 weeks along (for a single baby) although she's only at 28 weeks. That means that she's the size she would be if a single baby was full-term. From here on out it's probably going to get more uncomfortable. All in all, though, it's been smooth so far.
Anyway, just wanted to update everyone on what we found out.