Dear Mechanic, unfortunately rules file + wordlist do not work on multi-gpu 
Example:
cudaHashcat64.exe -a 0 -m 2500 --session=s6 -r bf.rule -w 2 --gpu-temp-abort=90 --gpu-temp-retain=90 -o "D:\keys\hash_found.txt" --outfile-format=3 D:\keys\step6\out80.hccap "D:\wordlist\concentrate"
Example:
cudaHashcat64.exe -a 0 -m 2500 --session=s6 -r bf.rule -w 2 --gpu-temp-abort=90 --gpu-temp-retain=90 -o "D:\keys\hash_found.txt" --outfile-format=3 D:\keys\step6\out80.hccap "D:\wordlist\concentrate"
Quote:Session.Name...: s6
Status.........: Running
Rules.Type.....: File (bf.rule)
Input.Mode.....: File (D:\wordlist\concentrate/06)
Hash.Target....: ******* (********* <-> *********)
Hash.Type......: WPA/WPA2
Time.Started...: Sat Mar 14 21:49:16 2015 (9 secs)
Time.Estimated.: Sat Mar 14 22:06:12 2015 (16 mins, 42 secs)
Speed.GPU.#1...: 0 H/s
Speed.GPU.#2...: 115.8 kH/s
Speed.GPU.#3...: 0 H/s
Speed.GPU.#*...: 115.8 kH/s
Recovered......: 0/1 (0.00%) Digests, 0/1 (0.00%) Salts
Progress.......: 1142790/115421790 (0.99%)
Skipped........: 0/1142790 (0.00%)
Rejected.......: 0/1142790 (0.00%)
Restore.Point..: 0/10389 (0.00%)
HWMon.GPU.#1...: 0% Util, 60c Temp, N/A Fan
HWMon.GPU.#2...: 0% Util, 55c Temp, N/A Fan
HWMon.GPU.#3...: 95% Util, 72c Temp, N/A Fan