How many eggs can you fit under a Silkie?

[pathognomonic]

I'm looking to hatch out a relatively small number of eggs (less than 70) next spring and summer. I don't want to invest in a good brooder for such a small number of eggs and I learned my lesson this year about the cheaper brooders. Against my better judgement I tried one out, but stopped the "hatch" at day 14 when it was clear that no matter what I did, the humidity level was just barely adequate for even that early stage (who reviews those things anyway??). I had a nice Cochin gal raising a clutch at the same time, she rather outperformed the brooder, to say the least.
I am looking to get some hens that will make nice mommas for me. I live in Central Kentucky and the summers can get quite hot. My heavy breed layers struggle some, for the Cochin it's really a challenge. I would prefer to use bantams, it's easier to keep them protected from the weather in the winter than help the heavy girls out in the summer.
The question is...how many standard-size eggs can you fit under a Silkie? I'm not trying to hatch out monster eggs, but they will be medium to large eggs.

 

[WVduckchick]

How big are your silkies? My guess would be 6-8 eggs, less if she's smaller.

Old English hens are also very good broodies, but they are so small, 4-5 regular eggs would be about their limit, but might be another consideration for you?