I’m still using cvs, not RC version but I’m sure there won’t be much, if any, change.
“All Faces” means as it suggests, that any face that comes within the radius of the current brush will receive some weight on its vertices. The radius is visible if the brush is moved while active.
“Vertex Dist” affects the application of weight to a vertex based on its distance from the brush centre. The further away it is, the less weight it receives but weight increases if the brush is moved toward it. It works best if “Soft” is also turned on - otherwise it is basically the same as painting with “All Faces” turned off as it applies weight evenly to vertices within a specified region.
If you turn “All Faces” and “Vertex Dist” off, then with weight set to 1.00, equal weight (1.0) will be applied to every vertex forming the face immediately under the brush tip. No radius will be shown as it is irrelevant.
If you turn on only “All Faces” then you will see a radius as you move the brush and note that every vertex of every face touched by the radius will receive equal weight - that’s why you appear to be painting outside the radius - you are. Setting the radius extremely small contradicts the general point of “All Faces” unless by small you mean small enough to still touch more than one face.
“Soft” is pretty obvious - it fades the region of influence when used together with Vertex Dist.
Various combinations of the three buttons will appear to deliver the same results but the best way to come to grips with them is to just subdivide (four or five times) and subsurf a regular cube. Turn on “Wire” in weight Mode then play around. Note: Turn “Optimal Draw” on in the subsurf modifier as I’m pretty sure the paint brush ignores the virtual edges generate by the modifier and only paints real geometry (this “may” explain the apparent “nothing” that sometimes happens as subsurf can often disguise the true location of the face you think you’re painting. Optimal draw won’t fix the worst cases of this but it will make it a little easier for you to see real faces and not waste time painting edges that don’t even exist).
The rate at which the weight is applied is controlled by the Opacity slider (or buttons). If you’re finding the change too slow, push the opacity up. Note that weight applies between vertices so even if Soft is turned off, the edges of painted regions will still appear soft as the weight must transition from painted to unpainted vertices.
As for the other buttons, hmmm - I haven’t used them and can’t advise. Some are obvious, others less so.
I really do not wish to revert to creating manual vertice groups on my armatures
In my experience (very limited), manually creating vertex groups can be a very efficient way of creating major weight regions - often much faster and more accurate than painting. Face-Loop selection is very useful here. I use weight painting to touch-up the crossover regions affected by more than one bone rather than generating major areas of full weight.
One very quick methodology is to select a bone in Pose Mode, switch to weight mode (or select bone while in weight mode!), quickly paint just one associated vertex to automatically create a correctly named vertex group then switch to edit mode, select all associated vertices/faces using loop selects, B-key select, etc, then “Assign” these to the selected vertex group. Switch back to Weight Mode if you want/need to soften up edges. This should get 80-90% of the assignments done - after that it’s down to careful adjustment with painting.