efi setup for windows10 and slackware

I recently got a refirb desktop running windows 10 on a ssd (/devsda) with the idea of adding slackware 14.2-current. I also added a second ssd (/devsdb) on which I have successfully loaded slackware 14.2 current. Here is my problem:
When I shrunk the windows partition and added slackware on /dev/sda I used lilo instead of going through the efi routine. I learned my lesson and installed slackware correctly on /dev/sdb and I can boot to it now. But I now cannot boot to windows on the other disk. Here is the partition table /dev/sda:

1007.0 kb free space
1 350 mb Microsoft basic data
2 202 mb Microsoft basic data
940.0 kb free space
4 274.2 gb linux file system
3 750.0 windows re
1.2 Mb free space.

and question is two-fold:
1) It looks like it is ok to use the 1007.0 kb free space for the efi space, is that correct?
2) if I do that will I be able to boot to /dev/sda as well as /dev/sdb as I can now.

I know this is a mess and I can get by with using slackware only but I do occasionally have need for windows so it would be a convenience to be able to access it as well.
Thanks for your help, jwc