V-Heart Cookie Cutter

Hi
I hope you can help me. This is my first 3D-project and I'm having some difficulties.
I'm using Cinema 4D R.13 and Illustrator. I know my Adobe Creative Suit pretty well and tried to understand C4D, too. More or less.

I'm working on a cookie cutter. I have the model now a I want it to be. Now I have some problems/questions:

1. In the shapeways tutorial for C4D it says:
I'm not sure if I did this correctly.


2. I don't know how to resize it properly so that it will be approximately 7x7 cm

3. What is the minimum wall thickness I should use for a cookie cutter if I produce it in "White, Strong & Flexible?"



I attached my C4D-file and would be really glad if someone could find the time and have a look at what I did. Thank you all!



edit: I figured it out all by myself

One question solved:

If I try to upload it, I get the error message:

I started over again and made a whole new version with the right sizes. I'm completely satisfied with how it looks and would want to produce it as it is.
But I'm nearly crying because I just can't get it to "connect to one object." Everything I tried turned out a complete mess. Party were missing or deformed.
I tried every video tutorial I could find and now I'm close to giving up.
Could you help me please?

The new version is attached.

edit: I figured it out all by myself

Where does it still say sandstone is 3mm?

Edit: OK, found it. The chart with all materials says 3mm, the sandstone page says 2mm. *sigh*