As for advice…
Pace yourself. It's about 200km all in with quite a few remote stretches so make sure you carry enough food to get you between re-stocking opportunities (basically Glenmore and Braemar). Don't carry too much. We did it with everything in rucksacks, including "evening wear", which was surprisingly heavy and caused arse pain within about a mile of setting off. You get used to it, but try to carry as little as you consider safe.
Nuun tablets for hydration are brilliant.
The singletrack from White Bridge into Glen Tilt is very good.
Glen Tilt is NOT downhill all the way, so don't relax when you hit the Falls of Tarf.
If you plan to eat in Glenmore, don't arrive too late or the cafe's will be shut and you'll have a long, hungry haul through some empty countryside before you arrive in Tomintoul.