The default interface ImgBurn uses is SPTI: you can change it in Tools -> Settings -> I/O tab, hit the Defaults button, answer No then click OK. You were able to overburn ~177 MB over the DVD+R disc standard 4,482 MB, which is pretty good although very unreliable.
Use the option "Write files/folders to disc" in ImgBurn, have a blank disc inside the burner and, as you add your files, ImgBurn will tell you how much space is left and how much (in percentage) of the disc's capacity is being used