Fetchsize tweaking (Oracle DB on a busy-ish MS SQL Server Reporting Services) - How big is too big?

First, my apologies if this is the wrong category, but I do think it's more a networking question than anything else.  It's also in that never-never land of using Oracle in a MS environment, so a relatively small group of people know a lot about both worlds.   And finally, I did originally ask this in a Microsoft forum, but it was suggested to ask this in an Oracle forum too.   So, here goes....

In an SQL Server Reporting Services (SSRS) 2017 environment, a busy-ish server, with multiple SQL Server and Oracle back ends, almost all on premises except for one Cloud based Oracle database, I ended up making the Oracle cloud connection fetch data about two to four times faster by upping the Fetchsize, in my case by modifying the 64 bit 4.0.30319 machine.config file for the managed ODP.Net connector (which is what SSRS mandates for Oracle connections).