Admittedly I am not a WU expert nor an API expert, but I do think it’s worth doing a few test uploads with smaller sizes to get an idea of the upload calculation. In Josh’s April post, the WU weights listed ‘0.5 WU for each item written to or modified in the database’. I’m not sure in this if ‘item’ is the same thing as a ‘thing’ (thing usually meaning a whole row) or simply 1 cell’s value per column. If it is a ‘thing’, 20K records should be around 10K WU, well within the 100K ‘free’ WU available in Dev. If so…it may be worth it to keep it all within Bubble and avoid the APIs necessary to/from.
We seem to use item and thing somewhat interchangeably. Lets say you have 100 products in your database (Product data type), we would say there are 100 things or items in your database of type Product. Hope this helps!