The idea of a second weekday has been raised before, the cons on the list were always that the people who make Tuesday may struggle to commit to a second day, and that might mean it wasn't successful... there is also the possibility that we could split the club between the people who prefer the different days, leading BOTH nights to struggle...
The last few weeks we've not exactly been packed at the club, with a shortage of space for tables or anything like that. If attendance was high enough that people may be missing out on gaming for a lack of space, I would be much more inclined to re-examine the issue. But if it's just that the few regulars don't get time to play all the cool games they want to play, I'm more likely to encourage them to meet up with each other on their own time. The club resources are frequently loaned out, could easily do this with Space Hulk too.