Hi, unfortunately those settings in the registry already are at 255. It looks like the TClockEx superseed the settings of the taskbar's system tray transparency albeit there are no settings within the app.
A few thoughts... and two questions:
What OS are you currently using and if it's windows 7/8.1, why are you still using TClockEx? From all appearances, TClockEx is a piece of software developed for Windows XP and still relevant with Vista, however massive UI implementation changes were enacted with Windows 7 and increased substantially with Windows 8/8.1... all of which play a role in how the user experience with WindowBlinds is.
Better, and far more customizable, software exists that would allow you to completely design your own UI overtop of Windows with a miniscule system footprint (if you so chose), and the same software can be used to create a custom clock on the Windows Taskbar ... Rainmeter [Rainmeter.net] is a limitless piece of software and something I would encourage you to check into.
All of the features TClockEx offers are all apart of Windows already, just not in a GUI form. While some can be changed via the system clock and and Control Panel, others would require you to manually edit the registry (TClock would implement it's changes one of two ways, or a combination of both, either by taking user input and running commands on the backend to edit the registry or it supplies it's own custom files (such as plugins) which implement the changes).
I personally would simply uninstall TClockEx and use Rainmeter, especially if you're running 7/8.1, as TClockEx was never intended to be compatible with those OSs and it is for this reason you're having compatibility problems. (Whether an piece of software will function is never the question, but how it will function within the confines of an OS it was never intended to be used on... in other words, just because an application works on a newer OS doesn't necessarily mean it's compatible with that OS - both are separate unto themselves and do not always influence one another).