Whatever you do, remember the old saying, "Bid what you want; but want what you bid."
For example, you might be able to hold a higher-positioned block in one base as compared to another, but what does that really mean? In the case of LGA and BOS, where there is only the narrow-body Airbus, it could mean a block of 1-day Shuttle trips that aren't commutable on at least one end. (DCA also has a lot of Shuttle flying, but also has 737 time. And DCA is getting more blocks in the new pilot bid, while BOS and LGA are not.)
That, combined with hotels that are expensive and/or far away from the airport, or overpriced, overcrowded crash pads has had many people regretting their bids.
Look at the commute, as well. There are only four flights a day between PIT and BOS, and two are RJ's. And on Saturday, the last departure from either city is around 3:30 p.m. Another night in the hotel. LGA does a little better with six each way during the week (3 RJ's), with the last Saturday flights around 4:00. In contrast, there are eight weekday flights between PIT and CLT, all of them mainline. (They do run several flights on RJ's on weekends.) You can get from PIT to CLT as late as 7:10 p.m. on Saturday, and there is an A321 from CLT to bit every day at 10:10 p.m.
The point is, a block ain't all it's chalked up to be, if the lifestyle that accompanies it stinks.