Washing Yeast from High Gravity Brew

I currently have small beers on two yeast strains that I am highly interested in culturing/washing for future use. Rogue Pacman and Chimay Trappist.

I have planned two higher gravity beers to pitch onto these yeast cakes in the next couple of weeks, and I am wondering if I will still have good yeast available to wash after a 1.090 or so beer has been pitched onto the cake?

I heard that it may be possible to "ressurect" the tired yeast, so to speak. Starting with a very small gravity starter and stepping it up and such.

without staining and using haemocytometer I wouldnt re-use that yeast after that high gravity batch.

that is kind of what I was thinking, maybe I will wash half of the yeast cake and pitch onto the other half.