Thank you for highlighting those papers. However, the VVIQ is not what I am looking for. It is not well constructed from the conceptual standpoint. Blazhenkova's (2016) Vividness of Object and Spatial Imagery Questionnaire (VSIQ) is an enhanced version of VVIQ.
Could you clarify the research question that you wish to address? What exactly do you mean by "consistency of visual imagery strategy", - how would you define that and what measurable properties would it consist of?
Nope. I am not obliged to reveal my research question on a public forum. As regards to "consistency", it means just that, namely the continuous use of the same strategy. I leave it to you to figure out my intentuon. Let me know if you know of such a scale. I'm currently making one, that's all I can say. ;-)