Somehow I missed this one also from Gresford. He mentions his neice Elizabeth Dovey.  
 
 
Usher, Reginald, Gresford, Denbigh, Farmer  
  Reginald Usher : will, 1792. 
http://hdl.handle.net/10107/884797These are the only others  in the Welsh Wills I can find, could be linked. 

Usher, George, Llanrhaeadr, Cross Foxes, Llanrhaeadr-ym-Mochnant, Denbigh, Innkeeper  
  George Usher : will, 1836. 
http://hdl.handle.net/10107/596787Usher, George, Bron-y-garth, St Martin's, Salop, Butcher  
  George Usher : will, 1837. 
http://hdl.handle.net/10107/464132Usher, Thomas, Llangynog, Montgomery, Miner/Yeoman  
  Thomas Usher : bond, 1738 
http://hdl.handle.net/10107/760970Usher, Thomas, Llangynog, Montgomery, Shopkeeper  
  Thomas Usher : bond, 1788. 
http://hdl.handle.net/10107/82987Usher, William, Fernhill, Whittington, Salop, The Elder/Yeoman  
  William Usher : will, 1810. 
http://hdl.handle.net/10107/833305