Invisafil by WonderFil might be a solution. It's 100wt polyester. It is not clear like the invisible thread, but it "sinks" into the fabric. You could use white Invisafil in both the bobbin and the needle. The white would sink into the dark blue of the batting, and it would work well on the top. No worries about "pokies". It's a good alternative to invisible thread: some machines don't like invisible thread ....