Looking for useful advice to use on TDEE and BMR

I am hoping some folks that have been doing this for a while will see this and give me some sound and correct advice. I have had things set up on MFP to their default setting but after reading some, I wanted to set them to custom and make sure my numbers were right. I have been to Scooby's workshop, fit 2 fat radio and read some posts on this site as well. I'm male, 40, 6'2 and 343 right now. I have a desk job but do some walking at work (maybe 2 hr a day of very light walking (2mph)) as well as normal stuff around the house. I have heard that based on that, to put myself as lightly active, but wondered if it should be sedentary since I am at a desk at least 6 hr a day. Also, there are several calculators for BMR which had me from 2864 to 2314. My TDEE was fluxuated between the different calculators also several hundred points. My BMI is 43.9 and bodyfat at 42.2. I just want to be able to set it up where I know what I have to (at least) eat every day and what not to go over. I also want to have it where I can eat back my exercise calories if I choose to do that. That is my story and I am hopeful for some real and useful help. Many thanks for anything you can send my way so I can get this right.