1) He's using D'Addario 1046.
2) Yes, you can put even 13-60 on a guitar with a floyd in D if you like. But you'll have to adjust the neck bow. And I'm not sure you're gonna cope with the addend tension on your fingers. The floyd might need more springs too and will need a setup for sure. 11-49 seems like a good idea, I tried 1046 and it was waaaay too floppy for me. I like 1046 in Eb.
I use ernie ball hybrid slinkies, nice light action on the top and normal gauge on the low to keep the crunch. Elixers are nice but abit too costly for me, i just use a string coat spray i got from our local shop works pretty good. I dont like heavy gauge strings too loose for me and im too lazy to adjust my guitar lol