Far too hard when you can simply visit a neighbouring country and return resetting your stay. Not sure why you would want to put yourself through this when there is just no need
When you are applying in your home country you use the equivalent of 65k baht a month in your own currency or 800k baht total equivalent again in your own currency. So if in the USA this is in dollars in your own account. You only need a thai bank account when you are wanting an extension inside of thailand.
I contacted the London embassy about this exact question as I travel 3 times a year for 2 months each to thailand so not there long enough to get the extension. The London office said that there is no limit as long as you meet the criteria