Due to a more gentle character of the procedure/treatment, I would propose to use lipofection. Electroporation is often more efficient however, more cells will be damaged in this process (compared to lipofection).
I had to work with this cell line before, I used both methods (electroporation and LTX) but non worked for me. Instead I recommend lentiviral transduction, or nucleofection.
I would suggest you to use AMAXA nucleofector technology. they have specialized program and kit. I myself used several time and it worked well for me. with AMAXA you will get good cell no. and better transfection efficiency. incase if you dont have AMAXA then try to prefer electropration over lipofectamine. however if you still want to use lipofectamine then use Lipo 3000.