Great, I will just remove FF# from all four flights and wait a bit until I have some new flights coming up, so that I can piece together some retro-claims to reach exactly 600 SP with 0 wasted SP.

There is time to retro-claim within 6 months of the travel date, so no rush. My membership year ends on 31 Jan 2025.

For example if I fly a brand new itin sometime this year that earns
+15 +25 +25 +15
which seems to be a pretty common scenario,
then I will retro-claim +80 from one of the aforementioned SEP flights to get to 550,
then retro-claim +25 +25 from the two new flights, get to Gold,
then retro-claim the remaining +80, +18, +18 from the SEP flights along with the remaining unclaimed +15, +15 in the new membership year to have a head start of 146 SP.