I was going to suggest them sharing a cot too. Friends of mine had their twins together for the first 3 - 4 months. I think maybe keep putting them both down at the same time & they might line up a bit better after a little while?
Even if one sleeps & one doesn't, if they have that same rest/quiet time each day, they might just decide to start settling into sleep when it happens.

I think 10 weeks is often a bit of a wonder week isn't it?? They become a little more aware of their surroundings, learn a little more & are a bit unsettled for a few days, then they settle again?