I've been a three-vessel all-grain brewer for years and I enjoy this type of setup, but there is something to be said for the portability of a single vessel system as well. For one, the latter is easier to take to club brewing days, not to mention the fact that it's so much simpler to store.
With that in mind I'm looking at building a "grainfather style" BIAB-ish setup. I'm on a tight budget so it's definitely DIY time. I'll be using an electric water urn which I will fit with a stainless steel grain basket, a magnetic drive pump and assorted plumbing, plus an electronic thermostat and thyristor-based power control. The latter will be able to "throttle down" the urn's 3kW element to a few watts to gently raise or maintain wort temperature.
The first question I've come up with is the grain basket. I have two options here: use mesh on all sides, or just at the bottom. Mesh on all sides has the advantage of reducing the risk of a stuck sparge, while having mesh only a the bottom will ensure a laminar flow that should optimize extraction efficiency (in that the water running through it has to flow through all parts of the grain bed on its way from top to bottom).
What are your thoughts on this? Which one would be preferable and why?