If the pipe will be inaccessible after installation, I would try to use a pair of 135° bends.
Think about how you would clean out the pipe if (when) it gets bunged up with soap scum and hair. There is more chance of getting a drain cleaning snake round a couple of shallow bends than a couple of right angle ones.
If they must be 90° bends, I prefer swept bends to knuckle bends for the same reason.
I prefer to use solvent weld pipe if it will be inaccessible after installation.