Kalico wrote:
I've been using a mix somewhere between 4:1:1 and 5:1:1 soft
sand:cement:lime for my pointing and block laying recently.

Is this about right for rendering? I only have a small area to do
where I have removed a window, about half inch thick.

Get a couple of small bags of washed sharp sand, & use 1:1:6.
Don't use soft sand.