JQuery/JavaScript Help

This is a small project for someone very experienced with Javascript, experience with Wordpress is helpful but not necessary. I have a Wordpress template that uses JQuery masonry to handle the way some content is displayed. It works, but sometimes only after 2 or 3 hard refreshes. Even though I have it set to load when the page is ready (not on load), it seems like it's running before all of the page elements are finished loading, which leaves weird spaces. I've tried shifting the code to the bottom of the page, placing it in an external file, but the problem is still there. I need to get it to run only once all of the page elements are loaded. I would also like to add on demand infinite scroll, but only once the masonry page load problem is taken care of. This is a template I wrote, and I'm not looking for a new template or someone to design one for me. I need assistance ONLY with the Javascript parts. All other coding/design will be done by me. When bidding, remember you are only bidding on help with the Javascript. I'm not looking for any plugins, or anything other than help with the Javascript. To filter for autobidders, send a message with "Javascript help" in the subject to be considered.