Personally I'd be reluctant to 'tinker' with giving anything, whether Help to Whelp, raspberry leaves, etc. The best way you can make things as easy as possible for her is to look after her during her pregnancy, with good quality foods, keep her calm and relaxed nearer the time, ensure you have her whelping area set up in good time and she's comfortable in that area, have everything that you think you'll need ready in plenty of time, plus having the things that you hope you wont need :-O Having a plan of action for when she whelps - where will other dogs/household members be? Having a plan of action laid out should you need veterinary help. Anything really that helps you feel completely ready for the whelping will all make it easier for her.
If there's a known whelping problem with your breed/line, then I'd be talking to your vet now.
Exciting times ahead :-)