Reusing Yeast From 2.5Gal APA to 5Gal IPA

Reading the suggestions on this site regarding reusing yeast usually point to washing/storing yeast for future use. I need to collect some canning jars in order to do that, but in the mean time I have a questions about just reusing the yeast cake in my 2.5 Gallon APA -- Wyeast 1056.

The APA (extract only if it makes a difference) has been sitting in a 3 gallon better bottle for almost two weeks & is almost ready to bottle. I'd like to try the Partial Mash IPA recipe below as a 5 gallon batch reusing the yeast cake from the 2.5 gallon batch.

Can this be done? What would be the appropriate procedure to accomplish this? Mrmalty says I need 109mL of yeast -- how do you measure that? How do I know if I have 109mL of yeast?

Extract 5 lbs Pale Malt Extract
Grain 4 lbs 2 Row
4 lbs Marris Otter
.5 lbs Melanoiden Malt
.5 lbs Belgian Caravienne
.25 lbs Honey Malt
.13 lbs Special Roast
Hops 1 oz Amarillo (20 minutes)
1 oz Citra (20 minutes)
1 oz Simcoe (20 minutes)
.5 oz Simcoe (5 minutes)
.5 oz Amarillo (5 minutes)
.5 oz Citra (5 minutes)
.5 oz Amarillo (Dry Hop)
.5 oz Citra (Dry Hop)
.5 oz Simcoe (Dry Hop)
Additives 1.5 tsp Gypsum (60 minutes)
Yeast American Ale II
OG 1.074

I'd just scoop out a cup of slurry to pitch and dump the rest

dcp27 said:

I'd just scoop out a cup of slurry to pitch and dump the rest

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basically