Kizuato...I love your version!!! ^ ^. Seventh heaven is not my favourite Kalafina's song, but your version is more...sweet..and more feminine.. I think...lol (even it's a male and female's voice instead of 3 girls..lol.)
Male's vocal is very calm and matched to the song, but I think it will be better if you can hold the steadiness of your voice when singing. Keiko always did it very well both in studio and live performance..^ ^.
For female's vocal.. I accepted that her voice is the female style that I love so much....

. However, there're some part that she's a bit off-key and/or can't sing it as powerful and steady as it should be... More practicing can make it better...^ ^.
It's take 2 for you.., and I believe that the next takes will be better and better... Practice makes perfect!!!

. I'll look forwards to your next recording...^ ^.