Dual boot of windows 10 and Chrome OS/ make your own high end chromebook

I wanted to dual boot chrome os and windows 10, but didn't want to go through the hassle of re-partitioning, re-installing, etc.  So, here is my alternative: Once you have followed my procedure, you will be able to boot into windows or chrome os. When a microsd is ejected, you can boot windows normally.  When a microsd card is inserted (and microsd is selected as the first boot device in the UEFI e.g. BIOS), you will be able to boot into chromeos.

I start out with a high-end Dell 7390 because I wanted a chromebook that was fast and had a 4k display without paying $800+ for a pixelbook (I got the 7390 on closeout at bestbuy for $590).  The machine came with windows 10 installed - you won't have to touch this installation.
Now the procedure:

1) This assumes you have a machine that uses UEFI (supports secure boot) instead of BIOS..most machines use UEFI now.  My procedure may work for BIOS and MBR, but I'm not sure since I don't have an old machine to test it.

2) You will need a usb drive, a very fast microsd card (This will be the boot drive, I used sandisk Extreme Pro SDXC), and a machine you can disconnect the main hard drive from. This system is just used to perform the software install onto the usb and microsd drives - it will need to boot from the usb drive and then install something to the microsd with no other hard drives available, or that can be seen.  The installer system will need to have either two usb ports (one of the ports will need a microsd card reader) or a usb port and a microsd card reader.

3) Ok, so here we go:  Download onto the "installer system", the cloudready usb maker located here:

https://www.neverware.com/freedownload

4) Insert the usb drive and run the usb maker..this will install the cloudready installer onto the usb

5) Once done, disconnect the normal hard drive from the "installer system", insert the usb drive and the microsd card into the "installer system". 

6) Boot off of the usb cloudready installer, enter all the usual info to get to the chromeos desktop

7) Click the clock on the right hand side..then click an option named "install os".  This will start the cloud ready install onto the microsd card.

8) It will take several minutes to partition, format and install the os onto the microsd card.

9) Remove the microsd card from the installer system, insert it into the machine you want to be the new chromebook, set UEFI to boot from the microsd card, and boot.

10) You should be all set to start using your new chromebook

By the way, for some reason after booting from the microsd card, and then shutting down, my computer wouldn't turn back on....this has to do something with booting off the microsd card latching up...the fix is pretty easy.  I just have to hold the power button for about 15-20 seconds until a charge drains from the card? and then it will reboot.  I'll have to read more about the cause of this....