My advice would be as follows:
1- start dieting for the show right now, you are way too fat, even at 4-5 months out. As a result, you've got your work cut out for you, that's for sure. You need to be well under 10% 12wks out to have any chance at retaining most of your muscle, being ripped and hard on show date. Period. The body just doesn't change well that fast. Starting heavier you can get down there, yup, but, you will be skinny and you won't be hard. This is especially important because you are well over the optimal height for a bodybuilder. This is a BIG genetic disadvantage you have for bodybuilding competition.
2- Get a knowledgable contest prep advisor. It will be worth whatever you pay. If you find a good one, thier first advice will be #1 above.