Well, it's all resolved now. (yes I am kicking myself that I didn't go with the NVMe!) but now i have a semi successful dual boot. typing this back on "7" since that's the one with bookmarks and firefox,. for now, but I was just pulling my hair out trying to find my way around "10" a few seconds ago.
Wow WHAT A CHORE this was. I thought I had done my research, but the whole day was plagued with problems, some of which were totally out of my control regardless of what I knew or didn't!
Steps for how it SHOULD have gone:
1 Shut down PC and install the new M.2
2 Use cloning tool to clone existing & install to new larger M.2
3 Power down, unplug old 7 drive so it can't boot.
4 Boot up to flash drive with Win10 install
5 Install Win 10 "custom" in new partition on un-allocated space on new M.2 drive.
6 Reboot and select which OS to install.
Done.
But, that's not how it went, from the start I should have known. Instead;
1 Shut down PC
2 Wait as Win7 decides to install last minute end of life updates
3 Wait longer as PC hangs for the first time in 5 years, choking on the updates.
4 Attempt multiple times to get the damn thing running again, unsuccessfully.
5 Cry as no matter what I di every time I try to boot, it insists on continuing to try to "finish the updates" and hangs
6 Try "safe mode" - fail, safe mode also tries to complete the update, and you guessed it, hangs.
7 Try system restore.
8 System restore successful, but that does not prevent the older 7 from trying to complete the update anyway, so we hang again.
9 Take wife and nephew out for dinner and an old school video arcade!!! 
10 Get home at 10:30 and give it another go. This time it finishes booting. No idea why. turn off all updating!
...go back to Step 1 in the first list!
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15 Boot to flash drive with 10 installation on it.
16 Begin install, select custom, select unallocated space
17 Get message that the drive I want to install on is MBR and Windows 10 requires "GPT" Can not install!
18 - 23 or so,. make several misteps in trying to figure out how to make it all work, including making the original 256gb SSD with Windows 7 on it completely unbootable.
24 Back to the intenet to research
25 Get live tech support on my laptop from easeUS Partition Manager (awesome app with AWESOME SUPPORT) because the license I just paid for to do the advance options of cloning, etc. is locked up on the Windows 7 drive that is unbootable, get new license info so I can;
26 Create PE boot flash drive with EaseUS Partition Manager utility on it.
27 Use that to reboot the workstation and fix the broken original install so it will boot... again.
28 back to step 2 in the first lest, reclone to M.2
29 use the same PE flash drive to convert that new clone to GPT.
30 Reboot with the OTHER flash deive with the 10 installation files
31 Go through 10 install again,.
32 Get to the place in custom install where I need to chose the unallocated space, get the message "Can not install on GPT drive!!!!!! WTF!?
33 More internet research!
34 Go into bios for the 20 somethingth time, and set all the boot and UEFI parameters for the umteenth time,. and ..
35 This time I get it all right!
36 Follow steps 5 and 6 and voila!
Oi, it's waaay past my bed time!
Good night all.
Tomorrow I will try to see what 10 will do with my hardware and software. In the meant time, I do know that one RAID array is not working in 10. No biggy, but it's exactly why I did the dual boot.