My company doesn't have a standard SG
Of course you don't use a standard SG in real operations.
If you read the thread you would realize we are talking about FCOM/AFMs, which use a standard SG where applicable otherwise every graph / weight and limitation would have to be published for all possible SGs.
The differing figures given in this thread are as a result of companies using different standard SGs in their manuals, most likely the most realistic SG for your location on the planet and what's your standard/most common fuel Jet A or Jet A1.
I seriously doubt your manuals publish limitations on every SG between 0.719 & 0.851
Ours are based on 0.785 with a few options to see 0.78 / 0.80 / 0.82
Lastly unless you send your SG to load control every sector they will be using a standard SG for weight and balance calculations, most likely based on statistical data provided by the airport or fuel company with likely seasonal changes to the SG.