What software did you use to put the captions on the photo? It should let you copy the pic onto a larger canvas so that you have a border around the picture where you could put the captions out of the way.
YouTube has a place for you to put a description, links, etc about your video. You could put a comment in there correcting your pommel/cantle slip. For future slips see if you can put subtitles/captions on the video.
I do understand letting go of perfection paralysis. This may not be the right place to do that as you are presenting your business here. Let me know if you want a step by step instructions on framing the pic to keep captions out of the way. It’s easy.
I do want to say it’s fantastic that you present the information without a lot of extraneous babble. Too many people make huge posts or 8min videos for things that can be said in two sentences. Keeping your intro short and getting straight to the point will get more views and more people coming back for the next one. If you want to explain in further detail just be wary of getting bogged down before the point or dragging things out afterwards.
Your video was very good. Having your sister already standing on the block would have shaved a few seconds and she could have demonstrated the incorrect hold as you explained, but otherwise well done. 