What you do kind of depends upon which monitor you have 426/tamama. If you are running 2560x1440 on a smaller monitor, you are frustrating your eyes. If you are on a 27" monitor, it can still be a bit difficult for someone with eyes like mine. Have you tried running at a compatible, lower resolution? If you are using 2560x1440 (16:9), try 1920x1080 (16:9), and see if that doesn't help make not just the stop watch larger, but everything else.
Barring that, what you want/need is
Larger_TMO_Stopwatches by razark
Instead of doing a 'regular' google search, use something like "site:subsim.com/radioroom larger stopwatch", or whatever you are looking for, but always name the "site:" like that. With a download, it is sometimes easier/quicker to click on the "Downloads" link above, then the "Search" function in that section of the site, and the terms.