for a long time+past simple

[ostap77]

"We graduated from high school in 1994 and I didn't see him for a long time after that."

Would it be OK to use the past simple with "for a long time" in this sentence?
Would it sound OK if I changed "after that" to "ever since"?

 

[Rover_KE]

"We graduated from high school in 1994 and I didn't see him for a long time after that."

Would it be OK to use the past simple with "for a long time" in this sentence? Yes.
Would it sound OK if I changed "after that" to "ever since"? No.

Rover