First up, as stated earlier, to start using the 800k the funds have to have been in your Thai bank for 2 months on day of application.
Funds not required to be shown came from abroad.
I use a dedicated bank account for immigration purposes and is definitely a good idea.
Personally, I would continue with the 65k monthly deposits until the day of application.
Overlap covers both options.
Agree with earlier post that WISE is probably best option for international transfers.
Edit: @Liquorice quoted you by mistake but will leave this post.