I have an awful lot of miners on the pool, most of which are running adhoc rigs of all shapes and sizes - a lot of them lower hashrate older generation hardware that will never make money mining but they run them as a lottery. 1k is fine as a compromise since ckpool adapts so quickly upwards anyway, in less than 30 seconds. If it was the era where you watch consoles which cgminer is running you could see it for yourself, but alas these days it's all hidden behind web interfaces and obfuscation. I've never heard of any rentals, even 8PH ones, having any trouble starting quickly on this pool.