hi @dch239 !! Welcome to our community 
Using the fixed size batch is not a hacky solution at all.
the dynamic size batch will calculate the amount of objects to send based on the latency of the connection to the server.
However, if your objects are big (for example, images), the size of your batches shouldn’t be defined by the number of objects to send, but by the size of each objects that are being sent.
On that case, using fixed size is more interesting, as you have a clear control of the size of the batch, and avoid to have a few big sized batches in favor of correctly sized batches depending on your objects.
Also, given enough resources, that is not a bottleneck, as you can increase the concurrent requests and have enough nodes on a cluster that can handle the load of your data.
Let me know if that helps.
Thanks!