Good question
@AzureDan
I have asked similar in the past as I am new to this and want to know what I am aiming for.
At this moment I use the link provided above as a guide and am glad to say my meter tells me I am in normal range with my readings. However I know people out there like them even lower than those numbers.
I am just waiting on my first HbA1c since diagnosis to tell me if this is the case or not I.e am i normal
Also like you I plan on gaining muscle ( whilst losing fat)
Good luck