I have put the environmental variables in the System->Advanced System Settings->Environmental variables, if this isn't where they were supposed to go please provide directions on where to put them. I have manually set page file in windows to 18GB to exceed the 16GB minimum you listed. When I try to use the -ethi 4 command it tells me it's not recognized. As you can see from my batch file below I put in a 60 second timer before the script is run. Any help you could provide would be much appreciated.
Environment variables go into the batch file you use to run the miner. There is a start.bat in the miner folder. Edit that and add your environment variables before you run the miner.
For example
setx GPU_FORCE_64BIT_PTR 0
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_SINGLE_ALLOC_PERCENT 100
ZecMiner64.exe
Also you mentioned the -ethi command isn't working. I believe that the command line can only handle a certain amount of variables. You have to use the config files (and why wouldn't you? I can't believe all the people that ignore them) if you have 3 or more commands on the command line. I think if you try the config files you'll find the -ethi 4 command will work. There should also be a config file in the root of your Claymore Zcash miner folder. There you can also find fun things like epools which is a config of your backup pools. (epools is left over naming scheme from his ethereum miner.)