Right Eye: -4.25 diopters, Pupil Size of 6.2 mm and Cornea Thickness (CCT) of 485 microns (avg)

Left Eye: -3.50 diopters, Pupil size of 6.3 mm and Cornea Thickness (CCT) of 487 microns (avg)

Corneal Curvature is 42
No astigmatism in either eye
No other eye disease, complication, history or problem
After doing some reading on the internet I estimate I will loose about 85 microns or so of cornea with a custom Laser intervention given my current prescription.
I am a 30 year old male and have been examined by two doctors.

First doctor who does LASIK said I was a good candidate for custom LASIK even though my corneas are a little thinner than usual. He'd make a thinner flap of about 115 microns with IntraLase. Even with the thin corneas there will be no additional risks for now or later complications.

Second doctor said Refractive Surface Ablation (custom PRK) is better than LASIK for various other reasons (delayed recovery aside) and with thin corneas that have a corneal curvature under 43 it's the right choice over LASIK anyway. But since my CCT is under 500, he would not perform the surgery on me and would also advise me against it.

Questions:

1. Is it worth other opinions (3rd or a 4th)?

2. Is it possible that with additional CCT measurements the reading can change significantly such that they go over 500 (ultrasound pachymetry was used by both doctors)?

3. Does race and heritage play a significant role in CCT and does a CCT of under 500 raise the same risks for all (I am of south east Asian decent)?

4. If I still went ahead with custom PRK, is it possible to know by what factor does my risk increase for Keratoconus or other problems that are associated with thin corneas (25%, 50%, 200% etc. or significant/insignificant)?

Thanks in advance.