Double distilling with the T500 Distillation System will have minimal effect on increasing the alcohol by volume (ABV).
When using the T500, the distillate will already have an ABV of approximately 90-93%, which is close to the maximum ABV achievable with a home still. Double or triple distilling is typically used with pot stills to replicate the outcome of a reflux still.
It's important to note that the highest possible alcohol percentage is 95.6% ABV.