don’t use an agent. The LTR process is very user friendly through the BOI website. The staff is also very helpful and will guide you through the process.
There is a checklist on the sight so you submit all the required documents. If they want additional documents they will ask for it. If you have questions send them an email, they are very responsive.
I did the same…Except I also have Google Voice for making calls over WiFi when I need to call the US. I just use my Tello number for Text to receive passcodes.