My direct experience isn't a "story", is real, I spent a lot of hours trying to use a GPU miner. This is my wallett address: FWqSdiERNp9i3dtE1M1ARbH4W1imgi1r29
and as You con see here http://explorer.fujicoin.org/ I started the mining months ago, always only with CPU because GPU never worked.

These are all the miner I tried, logically not all are for fujicoin:

https://s14.postimg.org/w9ap4kbu9/screenshot.173.jpg

but just for an example these are the results with the last sgminer (sgminer-5.6.1-nicehash-51-windows-i386) with some settings:

1) the setting You suggest on the official site, wrote in a file .bat

sgminer.exe --nfactor 11 -o stratum+tcp://cryptogrinder.com:5032 -u FWqSdiERNp9i3dtE1M1ARbH4W1imgi1r29 -p x

https://s14.postimg.org/hh5zcxg41/screenshot.174.jpg

only Hardware Error

2) the setting above changing difficulty

sgminer.exe --nfactor 11 -o stratum+tcp://cryptogrinder.com:5006 -u FWqSdiERNp9i3dtE1M1ARbH4W1imgi1r29 -p x

same reults...only Hardware error
https://s14.postimg.org/rfqxztxdt/screenshot.176.jpg

3) trying to use some tips found on internet the .bat file become:
set GPU_FORCE_64BIT_PTR 1
set GPU_MAX_HEAP_SIZE 100
set GPU_USE_SYNC_OBJECTS 1
set GPU_MAX_ALLOC_PERCENT 100
set GPU_SINGLE_ALLOC_PERCENT 100
sgminer.exe --nfactor 11 -o stratum+tcp://cryptogrinder.com:5032 -u FWqSdiERNp9i3dtE1M1ARbH4W1imgi1r29 -p x

Try to guess the result? only Harware error....

I can continue with another 20/30 different tries using the miners wrote in my first post, the only result got is...Hardware error or  "low difficulty rejected".