Correct your .pos as usual. Then use @jurijs.jeshkins piece of software in conjunction with your Reachview survey CSV. Done!
In RTKPost you will have to manually trim time interval to match points as @wizprod suggests . Reachview CSV is in UTC which is 18 leapseconds offset from GPST as default in RTKPost. (The software above calculates this for you). Not bad for 5 points but there is a better use of your time…
I let rover log whole time, just be cognitive of where it is (i.e. don’t throw receiver inside cab of truck then jump out to collect GCP for 5 seconds…)
I got something else cooking too but not ready.