Thank you, only thing I wouldn't buy the fc/esc combo again, going to build your 4" frame with 4 different esc in few days ;)

Why not the fc esc combo?

Yeah I'd also like to know of any issues with the XJB stack.

I have an hs1177 but I wanted to make it something like this http://rotorbuilds.com/build/364 so I can try also 3.5". But I'm worried about vibrations cause props would spin over the stack and of motor getting too hot with 3.5 props. I don't live in the US and I could find only this with a good price, you think it's not original? Also I'd like to run dshot, 600 but I couldn't find if omnibus f4 pro v2 supports it or I should go for the f3 pro. Thanks for yor help

I believe that FC I linked will support dshot. I have the F3 Omnibus clone and it supports it.

How about the 3.5" props what you think about spinning over the shaft, I will get any improvement over the 3"? I found this ones that should be the militia brothers triple diamond 3530 http://s.aliexpress.com/qQZ7rAFV

I don't think 3.5" props are really worth considering. It's got plenty of power with just 3" and you've got some great options in that department. I doubt you'll find 3.5" props with the same quality and performance as RaceKraft or RoxorX.

With the clone you suggested me I would be able to see the voltage of the battery in the osd?

Yes, it has vbat and OSD, so you can monitor your voltage, but not your current.

The voltage is enough, now I just have to figure out all the wiring to get everything to work with 4in1. I also want to add a buzzer for lost alarm and also voltage if possible

The 4-in-1 makes things really easy. You should get a plug that'll connect the FC to the ESC board. Then all you need to do is solder the motors and power leads to the ESC board, solder the ESC to the FC and wire up your RX and VTX/Camera.

Yes i'm reading about the right and best way to do all the wiring with this board. I hope it will be an enough durable build, more than a 5", thank you for your help!