Tables with len <5 possible?

First of all I want to say this is an absolutely awesome piece of software and runs super fast on a GTX 580, it's very impressive.
I have a few questions. I'm downloading the NTLM 8,7 and 6 sets of tables, I've generated my own length 5 table but the parameter for length doesn't accept 4 or below, is there a reason for this?
I realise that tables for smaller lengths are less useful because you can probably brute force these pretty fast without rainbow tables, especially on a fast GPU, but I wanted to gather enough tools to deal with plaintexts of length 1-8 inclusive, is there any way I can either generate rainbow tables for length 1-4 or use Cryptohaze to run without rainbow tables?
Does anyone have a good suggestion for a replacement application if this isn't possible?
I have a few questions. I'm downloading the NTLM 8,7 and 6 sets of tables, I've generated my own length 5 table but the parameter for length doesn't accept 4 or below, is there a reason for this?
I realise that tables for smaller lengths are less useful because you can probably brute force these pretty fast without rainbow tables, especially on a fast GPU, but I wanted to gather enough tools to deal with plaintexts of length 1-8 inclusive, is there any way I can either generate rainbow tables for length 1-4 or use Cryptohaze to run without rainbow tables?
Does anyone have a good suggestion for a replacement application if this isn't possible?