When I got my perlicks I was told put 10 foot lines on and slowly trim them back 6 inches at a time until I got the speed of pour I was looking for. I ended up leaving them at about 9 feet because the pour was fast enough for me.
Long lines will not hamper head or carbonation. Short lines can however increase foam on the pour. This is not really head. The size of the head is determined by carbonation and proteins or nucleation sites in the beer. In other words you don't need to over carbonate a beer to have good head on pouring.
Your foam is likely overcarbonation based on the description of how you carbonate combined with lines that are likely a bit short. My advice is get longer lines...diameter isn't that much of an issue but to dial in carbonation you should consider the size along with temperature and target vol level.
So keg one, determine the vol level you want for the beer, set the gas pressure appropriately and leave it alone for a couple of weeks. Just like you would carbing in a bottle. Once you've had success then you can play around with quick carbing to determine the best process for your setup but 3 days at 30 would be excessive on my system. Good luck!