Skip the little 90 degree L-bench and use a 75-80 degree bench angle.
Unless you have great mobility and strict form, you usually end up arched aggressively with shoulder blades sitting on top of the bench. Granted, plenty of guys do an incline bench press with poor lower back support, defeating the purpose of sitting versus standing. But a slight incline allows you to press at a shoulder-friendly angle.
Raise your arms upward straight in front of you until they're overhead. Are you able to raise them perfectly vertical without arching your lower back? If not you probably can't do a strict standing press without arching your back beyond what's natural.
Many of us don't possess the thoracic mobility to get into this position, so we'll create the arch through our lumbar spine. Not good. Avoid stressing the lower back needlessly, or worse, explosively blasting the humerus into its shoulder socket repeatedly until the rotator cuff tendons shred into pulled pork.
Avoid that scenario by building bulletproof shoulders and using a bit of an incline for your heavy overhead pressing.