why would you freak out over filling in a form. People book flights on line, buy stuff on line, but become freaked out over putting travel info on an online form.
if you are wanting a bank account you can apply for the non O in your home country and then arrive and open a bank account. After that apply for 12 month extension on retirement basis. But buying a property doesn't require Thai bank account or visa as far as I know.
The "3 days" seems to confuse people. 3 is 3. It's not 4 it's not 6 or 10. It's 3. Just count backwards from day of arrival. Apply on any of those 3 days.