As a newbie, you should evaluate your needs. First, don't listen to your LDS if they are pushing you to the most expensive regulators. Second, don't buy a regulator for future "tech" diving. If you are tech diving you will need double tanks, so that means purchasing more regulators. If you want to reuse your singles for doubles then I would recommend either the MK-25 / G-260, S-620, S-600 combo or the Apeks DST/XTX40 or 50. These first stages will be the most flexible for hose routing. Even if you don't plan on reusing the regulators for doubles diving, I would still make the same recommendation because you can use your singles set as a spare in case you run into issues with your doubles set and need to swap out the first or second stage.
I would recommend watching the Dive Rite Videos on singles setups. UTD, Coastal Development and others also have videos on singles and doubles setup. I also recommend reading " The Fundamentals of Better Diving" to see what a technical configuration is.