I have two observations to make. The first is that merely adding the votes of Wild Rose and the PCs and presuming that will obtain in the next election is false. The CPC never totaled the vote of The federal Pc and Alliance/Reform. There will be some leakage as the more socially progressive vote goes elsewhere.
The second is that uniting 2 parties to win one election is unwise and smacks of rank lust for power. Also, this hastened union might be pretty uncomfortable for members at either extreme. Perhaps the old adage (when divorce was difficult) "Wed in haste, repent at leisure" might apply.