There are three versions of most of the 200+ pages in this site.
A simple way. Control + should increase the size. Control - should reduce it.
Or to change the text size go to "view" on your browser tools line and select "Font Size", "Text Size", "Text Zoom" or "Zoom" of something that means change the size of the text. Select larger or smaller as you choose.
You can usually change the text size on any page using "control +" or "control -".
I'm interested that you found the site less readable because of the large size text fonts.
My experience in visiting people in their homes is that people have their computers set up to display a lot of information on the desktop. Then they struggle to read the text on most web pages, which are often designed by young people and where getting a lot on a page seems to be important. Most people don't know what to do about that.
In quite a few of the homes (not the majority) I find they have increased the text size their browser uses to make sites more readable. (Never the other way around.) So my conclusion is that in most sites text is far too small, OK for printing, but hopeless for on screen reading.
My own experience is that I can read my own pages for quite long periods on-screen. Usually one can't do that. This is important, because printing is expensive for most people. +30c a page in New Zealand with a bubble jet printer. Besides most people don't have a printer that works. I also make printer ready pages available, so pages can be printed in a compact paper saving way. If you really want small size text, read those pages. You can of course enlarge the small text if you prefer.
So my set up is unusual, yes, but I believe there are good reasons for that. Not to say I've got it exactly right, we will see. On all my "index" pages there is a link to this page to explain the Font Size policy.
So thanks for the feedback. You have caused me to think again about my decision, but I'm sticking with my present idea for now. (Further feedback on this or any other topic is requested.)