I do not know about importance of fresh or dried leaves, however think the problem with home made RLT would be that you cannot be certain of the concentration of active ingredient. Too little and it is likely to be useless, too much and you may increase risks, I think.
There was an Australian study @ 1992 which seems to be the main evidence body for the use of RLT, mainly to make the 2nd stage swift and there were less instrumental deliveries in the women who took it than those who did not.
I took RLT tablets for convenience of use as I did not always had access to hot water for tea, also I did not particularly like taste . I thinks the dose was 400mg twice daily, but cannot remember exactly. I still went 10 days overdue but had brilliant quick labour and delivery, 5 hours all in, and am dead proud I had the VBAC I was after .
I hope you find somebody who will waffle less and know more about dried vs fresh. Good luck!
It is easy to make fresh raspberry leaf tea. Strength is not so much the problem, as long as you are due and not in your first trimester, but that seems a fairly safe assumption. Most women drink cups and cups of the stuff without anything happening.
I would be more concerned about getting hold of leaves that are not covered in huge amounts of pesticides. Or do you grown them in your garden.
Basic recipe would be a loose handful of leaves in a pint of boiling water and leave to steep for about 10mins.
Must say I have not tried this with rl, only with lots of other herbs.