How to format and where to put the SPF TXT record?
Our SPF records look like this:
@ 1800 IN TXT "v=spf1" "a" "mx" "ip4:x.x.x.x" "ptr:example2.org.au" "mx.example.org.au" "ip4:x.x.x.x" "ip4:y.y.y.y" "a:example2.org.au" "+all"
The equivalent text is:
v=spf1 a mx ip4:x.x.x.x ptr:example2.org.au mx.example.org.au ip4:x.x.x.x ip4:y.y.y.y a:example2.org.au +all
So your guestimate record is very close.