Hi Jony,
After doing some research and confirmed by some senior members, we find that it is not feasible to send messages over 35MB. Currently, in Office 365, the message size limit is 25MB.
For more detailed information, here is an article for your reference:
technet.microsoft.com/.../exchange-online-limits.aspx
However, Jony, I must admit that your requirement is reasonable. In some cases, users do need to send large emails. Your idea is very useful and it will improve Office 365 services. So, I will write a detailed report and submit it to our product team.
You can also submit feedback to have our product teams hear your voice directly. They will look into the feedback and may improve the feature in the future. In fact, many features of our products are designed or upgraded based on customers’ feedback. Your efforts will be highly appreciated.
Best Regards,
Richard Ji