just continue to collect free olives until you can purchase an AD

Actually it was a blast to use in blitz, but it will have limited use in GB.

Personally I suggest saving for a Moltke.

It can also be a blast in Blitz and still has usefull setups for GB.

pcl's are very limited in their use in blitz, using 2 guns will get you tired of it very soon,
km has nice ships to use in blitz all trough the line imo.

the only thing i do use PCL's for a lot if for CV escorts (but then again, a DD1 could also do that).

so imo you shouldn't invest in a PCL, but rather go for the moltke as suggested above.
imo the PCA is also better (or at least more usefull) than the PBB. 

Save for Moltke It is usefull in both Blitz and Gb.

I would advise against getting the Bayern, or any PCL.