micksmith said..
Don't know about race board sizing problems with Lockrack but surf sups are great using lockrack, so easy so fast so secure. No affiliation just a very happy user
For my allrounders they are good except I can't fit them because I carry the race board more than the allrounders.
If they were sold as singles so I could buy a wider one with kayak arms and a narrow one ( would still have to truncate it) with the shorter arms , but then they wouldn't fit the allrounders.