I've only used the no.4 on the shooting board for very large blocks, say 3"
but only for holding the work, as it the plane not riding in the track.
I have a 5 1/2 for work like that.
Sometimes I find grain orientation can be troublesome, as in flipping the work around
makes the end grain cut much nicer/easier.
Another tip if one has some offcuts, if you can find a deck of cards sized block
and use this for testing long grain so the edge doesn't get battered.
Good to keep incase one might think the lateral adjustment may have got a knock.
I've often thought of making a flippable dual purpose shooting board,
one for rough heavier cuts, and the other for light ones.
If you have taken a heavy cut into it already, then the work needs to extend too much beyond the unsupported edge.
Some use another squared stick on the non feedable edge shooting board like you have, to counteract spelching. (a bevel on the back of the stick is worth doing)
Worth noting that the longer plane can be easily used to make sure that the track what should be square to the stop is still accurate.
Tom