This is an awesome kit with so many options!
Why get only one model when you can get them all?
It's easy if you use magnets!
Just make sure you use medium and small magnets in the right places. Drill holes in the plastic and fill with green stuff. And voilà!
These are the different spots where I've used magnets:
Some are medium-sized, others smaller and thinner (depending on the weight of the plastic pieces).