一度に => all at once N3
を中心に => focused on; centered on~ N2
に[加「くわ」]えて/に[加「くわ」]え => In addition to A (not only A), B as well. N2
Lists, Examples
[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
といったところだ => Display an amount/level/degree A (程度) N1
Degree/ Level/Amount