Have to agree with 18greens, there is no point in stacking the odds against you.
I am sure the examiners take bumpy weather into account and will cut you some slack, but if you go out of limits on the ILS or it becomes unstable, then no matter what the reason he/she has no choice but to fail that part of the test.
All the very best for the re- test . Its most certainly less nerve racking the second time when you sit there waitng for the examiner to join you!
flyfish