ZFS stripe question

[Michael Monashev]

Hi!

I  have  for example 2 same disks: da0 - 500Gb and da2 - 500Gb. I make
ZFS stripe on it, and get 2x read speed.

If I have 2 same disk, but one of it have 2 slices: da0s1 - 200Gb and
da0s2 - 300Gb. After I make ZFS stripe on da0s2 and da2.
What would average read speed I  get? 2x or ((300+500)/500)x ?
What would stripe size I get? 800Gb or 600Gb?

Sorry for my English.

-- 
 Michael