Deliver Page: stating output file size

While my main wish would be the focus on bug fixes, there is one small feature on the Delivery Page that would make my life a lot easier: it would be great if I I could either put in a desired file size for the output file and DR would then adjust the bitrate accordingly or if DR would calculate the resulting file size upon my manual adjustment of the bit rate. This should include the audio file size according to my audio settings.

I am often given maximum filesizes for my deliveries and and want to get as close to that value as possible. Calculating this manually is cumbersome and usually not accurate.

Premiere Pro can predict final size.

It's never been reliable. I'm not sure it's possible to make it so with anything but CBR, which generally is the least desirable encoding option.

anything but CBR

I assumed the output is always CBR as there is no VBR option given, also no multiple passes option. Either way the resulting file size should not deviate too much from a decent stochastic calculation.
I don't know how far off Premiere or the Media Encoder is, but if it brings me within a few percent it will already save me a lot of time. And it should be easy to implement into the UI.

What about these two graphics disk space meters?
Instead percent it can displays size in MB.

it can displays size in MB

really? I could not find how.

it can displays size in MB

really? I could not find how.

No no, MB could be instead of percent.
I apologize for my English.

I assumed the output is always CBR

Depends on the codec. DNx is CBR, Cineform, ProRes and H.264 are not, for example.