You could find somewhere that has 4 wheel laser alignment and knows how to interpret the readings.
It depends on loads carried and normal driving behaviour but generally the readings should be in between a set of min-max ranges.
With a rear wheel drive car that is displaying this type of symptom, normally the track would be statically set to toe-in and when accelerating it would naturally tend to try to toe-out.
So, it may be worth setting the tracking to maximum toe-in for that particular model (with appropriate load settings, etc) and see if that makes any difference.
I would also look at tyres (pressures, rating, sizes, etc) to ensure that everything is where it should be. Check for uneven tyre wear which could indicate a suspension/steering component that is damaged or excessively worn.