, Tod is correct regarding what KL stipulates regarding documentation they require but, I've always found provided I had everything else that was required then, just a single 1-3 night reservation of a hostel / hotel (starting from the day you land in thailand) was enough. The last time I applied was 2 months ago and I was successful with a booking for a single night stay at a hostel. Also, the hotel opposite the embassy used to allow you to print out documentation (there was a office at the back, on the ground floor) but i'm not sure if they still provide this service as the last time I used them was in 2015 - once I had 'forgot' to purchase a onward flight and was able to purchase and print out my flight using their computer and printer (for a charge).
