The accuracy of your shooting in the standing position will not just depend on the stability of your hold. The importance of trigger control is massive in the standing position. That said the steadier you are the better, but just seeing the pattern and size of your hold might not allow you to improve things. Just dry firing on a light switch or something might give better improvement than recording your hold pattern without having a coach to pick things apart.
How much do you shoot in the standing position? I shoot more in the standing position than anything else, partly because it's the hardest and partly because I think it's the only position which improves results in the other two positions at the same time. Consider setting your gun up for maximum comfort in the standing position and compensating in the other steadier positions. Or at least moving the set up of the gun toward those that best suit standing. Having the scope too far back is deadly as far as balance is concerned.
May be try spending a lot of time shooting an easy stander, say 40 mm at 20 yards, and just get used to pounding it. This might give you a chance to think about your style without constantly straining to hit a target which is closer to your limits. Concentrate on being quick and precise with your trigger finger. It does the brain good to get used to see the blighters fall over, it should allow you to enjoy the position.
No one hits them all the time and no one holds the gun dead still, dig in and commit to each shot!