Hi!
With RODI systems, you need to think about the filter and, perhaps more importantly, is how you will set the filter up so that it is as easy as possible for you to make water, store it and use it for the water change. If you don't think about the entire system, you end up making things harder, not easier.
For a long time, I've used the
5 stage system from Bulk Reef Supply. They make a very solid product and have replacement parts easily available. I would likely wait for the Black Friday sale to start so that you get a good deal on it. Make sure to pick up replacements while you're at it.
I use the double carbon set up because my area uses chloramines in tap. You really need the double to eliminate them. I'm not sure where you're at.
I also use the single, combined DI resin as opposed to the double, single ones as my tap is soft as it is and they last a while. Again, your milage may vary and you may be better off with having two DI stages because of your well water. I'm assuming it's going to be on the harder side.
The unit I'm recommending comes with a TDS meter so you're set there. It's dual stage so you can see TDS going in and coming out. It also includes the flush kit that is very important to improve the life of your RO membrane.
Overall, I really like it. Never had a problem with it.
Lastly, while I don't use one, I've heard good things about their
booster pump kit. It should provide the pressure you need to operate within the appropriate limits.
In the end, you should be very happy with this system. It depends on how you end up setting up the entire process, though.
Let us know how it goes. Send pictures! Or, better yet, start a Build Thread!