Joe Workman Impact stack load question

I have a niggle that’s been bothering me and wondered if any of you or perhaps even Joe may be able to help with.

I am using the Impact stack in a 16:9 header with about 10-15 slides. Works lovely and I am really happy with it. The problem is initial load. the height of the Impact stack seems to be zero, and then when it loads its first slide, it shuffles everything down. This means that for a split second the page looks really weird and then jumps about before it looks OK. I really would like to stop this happening. The images in the header are web optimised and warehoused via Cloudflare.

You can see it happening here:

Even optimized 15 is a lot of images to load, I suspect that is causing the short delay you are experiencing.