I was asked to select winners a few months ago,
this is what I did to make it provably fair.
That might be a little complicated for many people (including me if I just quickly read over your post).
If @Mitch212 only has 100 participants or less for his next raffle, he might aswell put them in a simple list, tell us a block in the future and let the last 2 digits decide but that is totally up to him. I just wanted to let him know, that there's an easy and also provably fair way to do these sort of raffles