Hi Wilso,
It can be done, but depends which model 7x50 you have. The newer has a narrower ep (<26 mm od when guard removed) and can be adapted as shown here
https://www.cloudynights.com/topic/5...nd-mewlon-250/
Using this:
https://www.teleskop-express.de/shop...nderscope.html
The older finder has an ep od ~31 mm and the Teleskop Express collar won’t fit it, but you could make your own.
I particularly like the idea of the following Kokusai Kohki collar that allows focusing of Tak polar scope, but it is too narrow for finder:
https://www.google.com.au/search?q=k...8yvOpfYqeG3zM: