If you add CHAR(9) - which is a TAB - instead of adding a space, you will be able to format your output better, IMHO.
Ultimately, you may want to either attach a PDF of your report or use an Email Plug in that supports HTML formatting of the body of your email in order to get good readability.
PDF would have made sense, but some users want to see in body of message and it seems that iOS and Mac won't display PDF natively. Requires them to open attachment. Silly, I know.
You have other suggestions here and I wanted to add mine. I also had the need to send email in "columns" from FileMaker. It may also depend on the receiving email client, but see it any of this helps in some way:
I sometimes call it Variable-fixed-width reporting.
The concept is to "pad the columns" with spaces so that each "line" is the same length and it appears as columns.
If the receiving email is using a font that is not mono-spaced, some of the effect may be lost. The same can happen when you try to just use "TAB" characters, as the email may not intrept as intented.
See what you think and ignore if not helpful.