Does the captivate file size affect the end user?

Did your boss give you any reasons why they're concerned about file size or state why they're specifically targeting 1MB per minute? Performance in a Captivate file can be attributed to a number of different things. Device/computer the user is on, browser used, internet connection speed, internet provider, latency between the user and where the files are hosted, and/or performance of the website/intranet where the files are hosted. Likely a few other things but these would be fairly common.

When doing testing on trainings in my office I had people using identical notebooks and I received varying reports on how the trainings did. Almost everyone had no issues but a few people had problems which we discovered was a combination of a few different things I couldn't have anticipated for.

Unfortunately you'll never be able to create something that 100% of the people will never have an issue with. Most of the time everything will run great, but you'll occasionally get at least one person at some point that will have a problem.

I will move your question to the Captivate forum.

It size matters depends on bandwidth and on the device used. For desktop/laptop bandwidth is not so often a problem, but if the course is also watched on tablet/phone that could be different. Not only are those devices less powerful, but when they are not connected using WiFi the experience could be slow.

You didn't tell which kind of output you publish to? If you are using Captivate 9, try to use SVG's instead of bitmap images, they are much smaller. Images are not always the most important cause of bigger file size, audio clips and video do add a lot more to the size. If you use bitmap images (PNG, JPEG, GIF) be sure to create them at exact the resolution that you'll need in Captivate. Do not rescale those images in CP. Use shared actions, objects on the master slides, or timed for the rest of the project instead of having multiple copies everywhere.