Congrats on the new purchase! Great gun that you've found!
As for the rail, literally any Pic rail cover would work, tho u may need to trim for length. In which case, trim the side facing the trigger guard 😉
Be aware tho that doing so may make the pistol not fit some holsters with it mounted on the pistol.
As for carrying, safety on... That's all personal choice. Myself, I did for a year or so, the just went safety off, full time. It's ok when ur getting used to having a gun on, and learning to safely handle the gun.
But I'll be 100% honest, no matter how much ya train to tab that safety... I've had to draw and fire, and I'll be the first to say that if that happens, keep it as absolutely as simple as possible 😉
Again, I'm not trying to tell you how you should carry, or what's right or wrong for you. But at least practice a bit, safety off. Just in case. 😉
Ps- Eh. The rail. Tbh I'm still fighting the urge to just dremel mine off!