Speeding up bruteforce cracking time

[blacktraffic]

If there is a way to make it search the 8 character password using min and max of 5 uppercase letters in random positions and  min and max of 3 numbers in random positions. This would speed up cracking time significantly. Instead of looking through all the hashes in any random order like this... 87989943, BB48N679,BBBBBN98 . They would all have 5 uppercase and 3 numbers like this ... TAM43PR9, 8Q6MTW3D. not in fixed positions like this.. W9K8DS4H, Q4H6GW8K.

We can generate a hcmask file which has every possible way of arranging 5 upper, 3 digits to make 8 chars, e.g. 

ABCDEFGHIJKLMNOPQRSTUVWXYZ,0123456789,?1?1?1?1?1?2?2?2
ABCDEFGHIJKLMNOPQRSTUVWXYZ,0123456789,?1?1?1?1?2?1?2?2
...

then run with -a3 hash.txt mask.hcmask 

I guess the lazy way to generate would be to generate all possible combinations and then filter out any which don't match the 5 / 3 split criterion. The proper way would be to use recursion and only generate valid patterns.

(I might have a pop at this later, as it's pretty similar to the default on my home router.)