Thanks for that as I had written off batching due to not needing for locking purposes and wondered if smaller retrieval sizes would speed things up at all.

Smaller table after obfuscation: (see attachment) Before obfuscation may have looked like Firstname JOHN, MiddleName NULL, LastName Williams. The function calls an .dll assembly which inputs a string (FirstName...

Also any thoughts on this approach?

Select * INTO T1_Obfuscated FROM T1. (obfuscating only columns needed.) then dropping T1 and renaming T1_Obfuscated to T1. Not really too worried about space concerns....