Loosen the twin pinch bolts and tighten the end bolt.
Check it spins good!!
Then tighten the twin pinch bolts.
Then check the spin!!
Then tighten the end bolt. It should tighten up against the force of the twin pinch bolts so it shouldn't affect the spin. It just tightens the end bolt to stop it from coming loose.
Once done, recheck the spin!!
Check the lateral play in the cranks. If they move then its too loose and you haven't tightened them up enough!!