SDs show the spread of numbers. SDs convey the size of the difference between means of groups. SEMs are absolutely wrong for repeated measures. Most text should be in 25-30 pt. Detail should be in 20-25 pt.
Big fonts are easy to read.
With big fonts you'll have to be brief, because you won't have room to write too much. Headings should be in 40-200 pt. Fonts like these, without serifs, seem to look better for headings. Use italic or bold for emphasis. Avoid fancy fonts and underscore.