Anchor Light is just 1 syn per 12.5g! Doesnt sound a lot but cos most of it is air anyway you get a good bit - id say 2 syns worth is definitley plenty!
Well put your strawberries or whatever in the bowl, put it on the scales and then turn it on, it should come up 0g, then just squirt your cream until you get 12.5/25g's worth!