Who is the saviour in Titus?

I've always thought Titus was a gem, and have also had some fascinating exchanges with JW's due to the way it describes Jesus and God with identical terminology. In particular the use of "saviour" for both, with an ABABA(C)B structure to its use, in pairs throughout the letter:

God our saviour (Titus 1.3)
Christ Jesus our saviour (1.4)
God our saviour (2.10)
Jesus Christ our saviour (2.13)
God our saviour (3.4)
(saved … by the Holy Spirit – 3.5)
Jesus Christ our saviour (3.6)

It's interesting to see the Holy Spirit snuck in there between the final two as well. That said, it could be a suggestion that the whole letter is riffing off the credal statement (as assumed by some, including the NA28 editors) in 3.4-7, as the three persons of the Godhead are described as working salvation. This is of course followed with the phrase, Πιστὸς ὁ λόγος, "this is a faithful saying" (cf the identical phrase in 1 Tim. 1:15; 3:1; 4:9; 2 Tim. 2:11).

Two other brief unrelated notes:

1. Teaching vocabulary is seen throughout, in 1.9a, 9b, 10; 2.1, 7, 10. 
2. The language of "good works" is also throughout the letter, 
• works, good works ἔργοις ... ἔργον ἀγαθὸν (1.16) - are not possible for the disobedient
• good works καλῶν ἔργων (2.7, 14; 3.8, 14) - should be given as an example, and should be zealously pursued by the godly
• every good work πᾶν ἔργον ἀγαθὸν (3.1) - people should be ready for these
• works of righteousness ἔργων τῶν ἐν δικαιοσύνῃ  (3.5) - these works cannot save, but only God

Lots in this little letter, which we start this Sunday and will work through over five weeks.