wondering, was the balance the part you were worried about or was it the weight?
could you have reduced fuel and kept the flight short?
if memory serves there is 48 gals (US) useable on a PA28. you could reduce it to 24 gallons and it might work better for you.
I recall "TABS" being 17 gallons a side.
Have you considered this?
I still remember my private pilot checkride (40 years ago) and the examiner asked me how many I could carry in a PA28. I said 4 with enough gas to go around the pattern once. He laughed and we discussed it in detail.
How much does the girl weigh?