OK, I will add my .02 worth. I had a 3800, and now have a P800.
I have used the front feed for some of them, but have found that they all feed through the top feed OK, IF you set the thickness to 4 and the platen to Wide. Been doing it for 3-4 years without a problem. I constantly use Canson Photographique, Ilford Gold Fiber, Hamn Photo Silk Baryta and feed it through the top feeder.
The 'straight path' feed is troublesome on these papers. However, when I print fine art matte stuff, I do use it.
bob snow