Congratulations, great way to go. First a little perspective. Generally the biggest determinant of the sound of your system is going to be the sound quality of the components and their interplay… synergy or lack of synergy. By far. Then probably the room and setup and then quality and synergy of interconnects and power cords. Then which connection type you use… which will make a small difference or none at all depending on your equipment.
It is best to choose balanced interconnects if the internal design of the components are balanced and single ended if not. I have high quality components and the choice of balanced or not balanced made no difference in sound quality although the brand / quality of the interconnect sure does.
I recommend one meter interconnects. They need room to gently bend and only a small change in your system and you end up with a half meter being to short. I’ve tried it a couple times and it ended up being a disaster quickly. One meter is standard for a reason.