Pouring wort on yeast cake

[Jbrew]

Hello, Ive been reading a bit about reusing yeast and washing, but a couple of questions, sorry if they've already been answered.
I made a blonde ale that I'm gonna keg this week and I wana make a big wave clone golden ale and just rack it right on top of the yeast cake from the blonde ale like I saw in basic brewing video.
Should I use the whole yeast cake? Or is that too much yeast?
And Is the trub on the bottom a problem from one batch to the next?

Thank you, sorry again if these questions have been answered

 

[Jbrew]

Well I missed the thread made towards the bottom of the page, and it did answer most of my questions, but if using the entire yeast cake will be way over pitching yeast, how much yeast slurry should I use?

 

[flars]

I estimate 1 billion cells per milliliter when I harvest yeast and there is a lot of hop debris visible. I'll estimate up to 4 billion cells per milliliter when there is no visible hop debris. This is when break material along with hop debris has been been filtered out during the pour into the fermentor.