i really am unable to say exactly what machine a guy should be looking for, but in my opinion, you need a machine that has a bigger mass in the head area and base than the series 2 bridgeport has.
the reason for the needed mass [again in my opinion] is the extra mass absorbs harmonics which will give you MUCH better surface finishes across the table travel.
as before, your mileage WILL vary.

to the others that have successfully machined blocks on a series 2, i'm proud of you ! just because the machine in question may not be the best one to use, you are showing you have the needed skills to be able to accomplish your goals with what you have. that is what makes you good at what you do.
i have been forced to do the same thing over my career, and the feeling one gets from pulling off something others say is unlikely or impossible, is very unique to say the least !