Digital instructional tools, such as virtual manipulatives, have been widely adopted as an enhanced approach to inquiry-based learning. However, the optimal ratio of mobile devices to students in instructional settings remain controversial. This research introduced a counterbalanced quasi-experiment to compare the learning performance and group-process satisfaction (GS) of primary school students under various settings of mobile device-student ratios (1:1 or 1:m) and external scripts (ES, with or without). A total of 128 sixth graders (11 drop-outs in the second-round experiment) in four elementary-school classes adopted physics simulations on tablet PCs as virtual manipulatives (VMs). Group worksheets and posttests were administered during and after the inquiry process to assess students' inquiry performance and knowledge acquisition. The analyses revealed that students under the 1:m condition significantly outperformed their peers in the 1:1 condition in both subterms, concept understanding (CU) and problem-solving (PS), but no significant difference was found in knowledge acquisition (KA). ES showed no effect on students' learning performance. VMs that students used in collaborative tasks operated separately on each tablet PC, which may have distracted learners' joint attention. Hence, the collaboration patterns were observed and discussed. Four potential collaboration patterns are discussed at the end of this paper.