Since you have the flavors you have and you want to get started, my recommendation would be to try a few different OVERALL ratios in tester size (like 7% total flavoring, 9% total flavoring) maybe a fruits alone mix potentially which will need less steep time than the creams, and then a few where you actively decide, like "My dominant note will be creamy, my dominant cream note will be vanilla, I will try strawberry and vanilla and I will try vanilla peaches and cream in whatever like, percentages make sense in small volumes, and steep at least 10 days, and then start tasting stuff and see what matures, fades and/or does both and you can gain some valuable information that way as you are waiting and identifying some other flavorings (and also, you could order some one shots that you may find appealing which are premixed flavorings that are pretty much waiting to be shaken and vaped immediately after mixing, too, that's always kind of a nice way to get through the waiting game and etc., but there's no reason at ALL to not do some early experiments in very small batches as a lot of DIY is trial and error and about what YOUR tongue likes.
I actually took the very patient step of doing stand alones early and figuring out how individual flavors performed and steeped and my general percentages I tended to like, I would combine in my tank and not the same as steeping together but still enough to generate some early experiments and trial and error, and it did give me a knowledge base that kept building mainly because I started slowly. So no harm at all in going as slowly as you want and etc.
Best of luck, and go check out the DIY forum for more ideas, too.
Anna