With same powder, and same barrel (just cut shorter), and same bullet,, if QL results are good for 26" they'll be good for 24". But, this is based on your validation of correct results, from said powder/bullet/barrel.
If you're asking if QL is right without validation, the answer is maybe. Is a reloading manual right? Maybe..
It is impossible to predict with YOUR components, without some validation.
About 12yrs ago I sat down with cartridge design software, ballistic software, a blank reamer print, and QuickLoad, with intent to build the most efficient 26cal with 140gr bullets. Running 'what-is' with everything I came to the capacity needed with a wildcat very close to 260AI, but able to handle more pressure. A 26wssm Imp.What I'm asking is if anyone has used QL to estimate a load and then validated the QL results with actual chronograph data. If so how close were you?