The measurements of the Albatross are roughly synonymous (floor space wise) with the 5 metre bell. I find that about the right size for family camping.
Of course...more space is nice, but you've got to take into account pack size, weight, stability and most importantly, finding a suitable pitch.
The bigger you go, the more you have to compromise on location. So the Herring Gull might prove cumbersome from that pov. I think you were wise to choose the Albatross.
I agree that Karsten tents aren't as comely...I'm not that taken with the DeWaard tunnel tents either. I'd go for a pyramid tent every time.
In all my deliberations, I concluded my eventual upgrade (our current tent is in fine fettle and suits us well) would most likely be a Canvas and Cast bell of the same size again - 5 metres.
I am swayed by the ease of putting up, small pack size, good looks, reliability, floor space and affordability of your bog standard bell.
I'd still like to see that DeWaard though - if anything was to turn my head away from a bell tent, it would be one of those.