Bolt sizes?

I am having trouble finding the sizes of the bolts that are used to adjust the tension of the belts for a 99 eclipse. I have called dealers(got the wrong sizes), called and went to autozone and still I get nothing. I dont want to strip the treads trying different sizes so if anyone could help, It would be appriciated

What trim is it? We need to know what motor you have.

99 spyder eclipse non turbo 2.4L engine model 4G64