I don't think you are more or less likely to receive a transit whether you are VFR or IFR. It usually is purely based on how busy the CAS is.
Would the same be true of class D other than a control zone/area, eg. the Scottish TMA?
Let's say one was going to fly from Carlisle to Prestwick at FL065. Would it be more beneficial to be VFR or IFR upon reaching the TMA boundary in such a situation, indeed would permission to enter the TMA be forthcoming at that level?
Thanks