The admissions department at colleges know about the relative strengths and grading scales of the different high schools. Both of my kids are now through the college application process and in both cases, the colleges they applied to recalculate the GPAs to get them onto a common scale. So if your grades are out of a 4.0, 5.0, 6.0 or out of 100, never fear, the schools will figure it out.
As for the coaches, our experience was that they are using GPA as a screen. To quote a UCSD coach, the first thing I look at is can they play? If I think they can, the next thing is can they do the work? For that, they are basically looking for a yes no answer - and if there is a doubt, they will work with admissions to get an answer. Just list your GPA as it is shown on your report card under cumulative e.g. 4.2/4.0 W. My son always did his weighted and no one ever cared about that. Just put a W after the GPA.