Justin, I have nothing against Unique, but do you have a Cast Lighting distributor in your area? I am one of those Jersey guys, but not quite getting the numbers you were told. We use the Cast system and fixtures from other companies, adapted to work with the Cast system. So far the only callbacks have been to add fixtures or expand into other parts of the property. Check out Cast, they have excellent product and even better support. http://www.cast-lighting.com/index.html
On your pricing, I am comfortable with selling the products at suggested list price and including all the unforeseen parts. Extra wire nuts, landscape staples, soldering your splices, and any new tools or equipment needed to do the install properly. Your time for labor is about right. The install is not difficult, but you do need to wait till dark to make sure the lamps you have selected throw the correct beam and are the right brightness. Also fixture position may change as the sun fades. Usually you will buy some extra lamps to tweak your design. Different wattages for intensity and different beam spreads for impact or a subtle glow. You also have to account for your design time. If it's free, that's all it may be worth. If you have access to a 3D imaging program, you can get a great idea of what you want to accomplish with the lighting. The hub system is similar to Cast's spider splices so you are on the right track.
Figure out your material costs, labor, overhead and profit and you should be able to come up with a fair number for you and the client. If you use a "system" and follow it, your installation should be relatively simple and long lasting. Don't skip steps because it's easier or you don't have the right equipment. Do it right, get the right tools and charge accordingly and you will find lighting to be an excellent addition to your services. Especially at this time of year when most homeowners are coming home in the dark, let them enjoy the landscape and provide security as the days get shorter.