Researchers have recently suggested that teachers must undertake important dual self-regulation roles if they want to become effective at improving their students' self-regulation. First, teachers need to become proficient at self-regulated learning (SRL) themselves, and then teachers need to learn explicitly how to proactively teach SRL -- termed self-regulating teaching (SRT). Considering that both roles are difficult to attain by novice teachers, supports (prompts) are essential. We examined an intervention comparing the usefulness of two prompting conditions -- generic versus specific -- for developing both SRL (as learners) and SRT (as teachers) among 90 preservice science teachers engaging in explicit self-regulation instruction and reflective group discussion about learning/teaching experiences (observed learning clips, in-action teaching). We compared the two group conditions by using two SRL assessments and two SRT assessments. Mixed methods indicated that, as expected, the specific-prompts condition outperformed the generic-prompts condition on self-awareness of own SRL, skills for accurately noticing authentic videotaped students' SRL, and explicit usage of SRT during actual teaching experiences. As expected, no differences emerged between generic and specific prompts in applying SRT to a novel lesson-design task (far-transfer measure). These findings, supported by two case studies' sequential pattern analysis, offered an important contribution to theoretical and practical understanding of novice teachers' self-regulation prompting approaches, practice modes, and multidimensional assessments of teachers' professional development.