Also you don't need any proofs don't worry

I printed a form from the official website for Vientiane and was told to fill it in again using the form there (it was identical) you could try your luck but be prepared to fill it out twice.

I see, that makes sense

Taxi. I pay 20 baht when crossing but I figured that was a bit of "grease" for jumping the queue and using the private car booth. I also pay it to the immigration officer entering Thailand not leaving Laos so maybe taking a taxi avoids the nominal charge for Laos.

I've never paid this fee and crossed 6 or more times there.

you flying from Udon?

mmm you best go early in that case. Also i HIGHLY recommend taking a taxi from the consulate it costs more but a hell of a lot easier it will take you straight to the airport too. Pay no more than 1000 baht (possibly cheaper) even better get people to share it with you. The taxi will help you jump immigration queues too. (just pay a 20 baht "fee")

what times your flight?

bear in mind your application will not be avliabe until later on the pick up day because you will be nearly last in the que for returns. If you need to rush away the 2nd day you might have to go early actually

no point in going early, turn up around 9.30-10 when the que has died down for less waiting around. Going in at 6.30AM will not ensure a "short wait" lol