yes, 300, 600 and apparently 1030 maybe? these are times they come. and ur tama on v4.5 has to be 6 yrs old (i just got visited by the matchmaker on my 4.5, so i know).
i believe it's 72 hours or so after your tamagotchi has turned into an adult is when it can mate. the times the matchmaker comes are 10:30 am , 3:00pm and 7:00pm.
Yes, I agree with Vanilla. I think it is 72 unpaused hours after your tamagotchi has became an adult. If you pause it allegedly you might have to wait a while longer and the process is slower.