Acridine orange staining can be used for assaying DNA damage in sperm DNA under various conditions. However, studies have shown that The AO staining did not detect any differences between sperm cells preserved with different lyophilization media. However, differences in DNA integrity were observed among treatments with the TUNEL (terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling) assay, suggesting that TUNEL is a more sensitive method to evaluate sperm DNA.
Reference: Martins CF1, Dode MN, Báo SN, Rumpf R., Genet Mol Res. 2007 Mar 15;6(1):94-104
Your choice seems to be correct, as it was also tested in the paper of Elden M. Mohammed “Acridine Orange and Flow Cytometry: Which Is Better to Measure the Effect of Varicocele on Sperm DNA Integrity?”, published in Advances in Urology, vol. 2015 (2015), Article ID 814150, http://dx.doi.org/10.1155/2015/814150. Namely, semen analysis and sperm DNA damage expressed as the DNA fragmentation index using acridine orange staining and chromatin condensation test by flow cytometry were assessed concluded from this study. The authors concluded that acridine orange stain is more reliable method than flow cytometry in the evaluation of sperm DNA integrity.