Consistency is gonna be the biggest key here in this equation. You could do any set/reps sceme you feel most comfortable with and as long as you are hittin it hard every week you'll continue to see progress. With that said.....
I rarely ever utilize 2.5lb plates. I prefer to play more with reps in a ramp fashion with increasing weight. Possibly 125x10, 135x8, 145x6 on a bench and the next week possibly 125x12, 135x10, 145x8.....Now if i'm unable to complete i will repeat it the next week and so on. If you set rep goals and just try to reach them at 75-80% 1RM you should be able to make steady progress right now with the assumption your pretty new to the iron game.