I have concluded that however I divide the data I have, I am going to end up with unequal sample sizes. How important is this statistically?

Previously I had n1=24 and n2=16. JohnM very kindly helped me out and highlighted the reasons why my tests would be unfair with these figures.

I have another idea involving two groups where n1=43 and n2=55. How similar do sample sizes have to be for a statistical test to produce valid results?

Thanks very much for reading and helping the statistically challenged such as myself, this is a great forum.