You are the one there and can get a feel for things but I would want to be able to handle him pretty well before you let him out of the cage.
This is how I see the scene...open cage door, Mowgli slowly and cautiously leaves the cage, makes a sudden mad dash under a piece of furniture, and you never see him in the daylight again!
Don't ask me how I know this! You will have to be the judge of where you think things stand. I thought I was pretty smart when it came to Magoo and I let things happen too early and we all almost went nuts! I don't think it will that bad with Mowgli but my personal opinion is give him a few more days. I would really want him to look forward to being petted before I released him. Now mind you this is just my opinion and you are there and you have done such a wonderful job so far that I think you are a great judge of Mowgli.
Keep us posted on what you decide to do.