Have never used the script so can't say for certain, but looks like you've got them correct. One way to find out! Do it! (assuming your direct edits of tables will allow)
I thought Google had different requirements now ... port, TLS ... and it certainly has caps ... # of messages relayed in a day.
Now that you've described your issue and what you were up to, yes, makes sense now (not originally).
Comments: over the last year or so I had issues with a Google Compute Engine on CentOS 7 and a couple of sandbox moodles when attempting to use gmail as relay. As well as a Rackspace sandbox server. What Google giveth Google can take away ... and they have ... with 'fair warning' (less evil?)
RS at one time had a relationship with mailgun ... but that one required one to putz with DNS to make it work. Too much trouble!
So went 'shopping' ... found SendGrid to be enough for my needs.
This to suggest maybe you should 'shop around' some more!
Do know this for certain ... use to install/maintain/update mail gateways as well as Linux mail servers (spam/antivirus ... the works). Don't wanna do that any more! That's why I have thinning gray hair now! :\ So even if one might have to pay a fee, to me, worth every penny! (as long as there's a freebie 10,000 messages day in front).
Wishing you the best of luck!