Well, maybe a bit outdated and perhaps there are other solutions as well, but I would like to share how i made succesful transfer from my custom V4's to Sasha, might be useful to someone/somewhere :)

First of all, i installed Sasha in the directory where V4 base is installed (ofcourse [rolling_eyes] [rolling_eyes] )
secondly, i created an external runtime called "SASHA runtime" (how original [rolling_eyes] )
I loaded Sasha and injected all possible morphs : e.g ++, Steph 4, muscles, elite, badabing, i13 boombone,boomnose,uniquemorphs, ... anything, all of them ... you name it ...

I saved this as my base in the external runtime as well as in the original sasha16 setup folder.

To transform a custom V4 to sasha i simply load this base figure, i load my custom V4, select the head >> top left in poser >> edit>>copy . Then I select Sashahead and >>edit>>paste ... same for the body : select V4 body >> and do same as with the head .... now I apply same texture, hair ... to Sasha, delete V4 and there you go .. I save this new character into my sasharuntime and it works flawlessly everytime, morphs shapes, customizations (only dials) (no sculpting with external programs) are perfectly copied and reproduced on Sasha !!

Just wanted to share how "simple" the transfer of V4"s to Sasha works for me

Thank you for your magnifecent Sasha, Karina !!!

ps : I mostly work with poserpro2012 but i have p11 as well.