It is a really specific thing and depends on your settings, but maybe it could help you with the last problem. You can get some theoretical results on the amount of data needed for testing (that obviously gives you only very general idea on the amount of training data) using Hoeffding inequality.
FierceQuanta t1_iu9nz5z wrote
Reply to comment by raman_boom in [D] What are the bottlenecks in your ML project lifecycle? What tools would you like to see more widely used? by Fine-Topic-6127
It is a really specific thing and depends on your settings, but maybe it could help you with the last problem. You can get some theoretical results on the amount of data needed for testing (that obviously gives you only very general idea on the amount of training data) using Hoeffding inequality.