72 inside door panels on 70 doors

[70Stub]

From reading old posts, I understand the panels will fit but need to change window regulators and such because the 72 panels are wider than the 70 panels. I found spline extensions on ebay that extends the shafts out 5/8". How much do I need to extend the shafts? Would the 5/8" longer work? I already have the 72 panels, didnt realize they were wider when I got them several years ago. Thanks!