Regarding that technical article, there's a couple points in it that I've personally seen making system administrators uncomfortable and hesitant to follow through on the instructions.
Firstly, the article specifies "The domain account name must match the host name of the NLB". While the SPN certainly needs to include hostname and FQDN of the NLB as is documented, I've been told it shouldn't matter what the domain account is called so long as it is consistent throughout. Is there any requirements specific to ArcGIS that dictate this naming convention? If so, it may instill confidence if the article expanded upon this point.
The second issue I've seen raised, is that the -A syntax used in the setspn command has been long since deprecated, with Microsoft recommending everyone use -S. As far as I understand, the only reason anyone would have to use -A is if they were on Windows 2003 - for which extended support expired five years ago. Is there any reason to continue using -A syntax, or is it more the case that the article was written with compatibility in mind back when Windows 2003 was a supported operating environment?