Early sieving (around the first 160000P) on GFN22 only went to a maximum b level of 100M. We're now resieving to b=2G which we'll need at some point for Do You Feel Lucky. I'm sieving everything under p=5000P since those files are very long (gigabytes). Anyone doing this new low-p sieving should be prepared to compress their factor files using zip, 7zip or rar formats. While I can handle almost anything, those three formats are automatically unpacked by my scripts. The maximum file upload size is 40MB, so anything larger than that will not upload. I've put a big obnoxious warning on every manual sieving page, it includes links to email me factor files or PM me with a link to an online factor file. While I'd prefer that you upload within the sieving system, don't be shy about using those other methods if your file is just too large to fit.
And please, hang onto your factor files until you've received credit in the system. This means I was able to verify that the entire file made it to PrimeGrid and was able to unpack it. If there are any problems, the fastest way to get my attention is on our Discord channel (highlight me with @JimB) but of course I also check the forums several times day.