Limits
What runs out first is rarely the limit
A hundred megabytes per file and fifty files per task are generous. The constraints you meet are elsewhere.
The recipient's inbox
Most mail systems refuse attachments far below a hundred megabytes. A merged document of scanned pages hits that wall long before it hits ours.
The download window
Server conversions hold their results for sixty minutes. Fifty files converted at once have to be collected inside that hour, which argues for smaller groups when the files are large.
Your own attention
Fifty results is more than anyone checks properly. Twenty is a batch you will actually verify, which makes it the better number regardless of what the ceiling says.
The one with a clock on it
- Keep your converted file afterwards — a server-side result is held for 60 minutes and then deleted