Combining list and mask

[philsmd]

precompute one of the sides and use -a 1 ?

Code:

hashcat --stdout -a 6 -1 ?d?s --increment -o dict1_mod.txt dict1.txt ?1?1?1

Code:

hashcat -m 0 -a 1 -w 3 hash.txt dict1_mod.txt dict2.txt

note: I omitted -O on purpose, because I have no clue how large your words will be, but the performance will be much better with that restriction and -O added

an alternative could also be to use -j with a single rule and repeat that command for each character (rule) you want to use in the middle of the two dicts