Enve rim advice and spoke lacing question

[melac1]

Hey PL,
I'm putting together a track wheelset and have some questions before starting the build.
The rims are enve classic 45mm(24 rear and 20 front)
Hubs are dt swiss track.

First question is if enve classic 45mm require a special type of spoke nipple? Or if a regular nipple is fine.

My other question is regarding spoke pattern. I was thinking of 2x rear and radial front, but was wondering if I could do 2x front and 3x back with this little spokes or if it would even be worth it.

Thanks,
Calem