Standby to extend award stopover?

Hi all -- so sorry of this question has been asked, but I haven't seen this permutation before..I'm looking to book a SFO-LAX-LHR-(onwards) award ticket at some point in the near future, but I adore spending a day in Los Angeles with friends before continuing onwards.

Unfortunately, 24 hours for a stopover isn't enough for me in this city, and that's all that allowed by most frequent flyer programmes. Would it be OK if I were to tactically book an 11PM SFO-LAX departure, and then an LAX-LHR flight for the following evening, and then stand by for a 6AM SFO-LAX flight so as to extend my stay to >24 hours in LA? Does UA allowed standbys for 1P members on award tickets issued by partner airlines? Are SFO-LAX loads light enough to make this a reasonably fool-proof plan?

Thanks so much!

Edit: If UA adopts CO's +/- 24 hour confirmed standby policy, would this be a good situation where I might be able to use it to my advantage?

award tickets allow for one stopover and one open jaw. Provided you do not have a stopover elsewhere on the itin, you can take a stopover in LAX for as long as you want.

Otherwise, a connection is up to 24 hours.

Just to be clear, and please correct me if I'm wrong - it is one stopover OR one open jaw. We cannot have both on the same award.

Not familiar with the UA rules but it is certainly possible to do both on a CO reward ticket. OP could easily transfer miles between accounts if necessary.

They're both stopover and open jaw.