Sounds like its getting there.
I know its not much help in the immediate but a few suggestions that will make your set up a little easier to adjust and monitor.
it would be really handy to have at least one pressure gauge between the pre filters and ro (will help you keep a check on the condition of the filters and if they are getting blocked/need changing)
put an inline tds meter on the hose from pure outlet to di
as already mentioned, most prefer the di after tank and pump
change the waste valve to a metal needle one, you just won't get the fine adjustment you are going to need with that plastic tap. I even have mine set up (on vyairs recommendation) with a bypass and ball valve, so when the waste to pure ratio is set it is just a matter of opening or closing the bypass valve to flush or produce pure.
good luck with it