I have coated commercial liquid emulsion onto cheap watercolour paper without too many problems.
You might be interested in this thread
And a couple of examples from my experiments are here (same thread, just a direct link to one of my posts)
They are digital snaps of the coatings, not scans, because they hadn't quite dried, and I didn't want to gunge the scanner up. Yes, they are a bit foggy, because of my no-to-dark darkroom, as explained in the linked thread.
If I can find them, I'll scan them in properly and post them.
They were coated with a blade I built, inspired by PE's design, but made of plastic and with a couple of adjustments to the shape to help increase the stability of the lightweight blade.