Carl,
That's how I did my Panther as well.

I used water based vinyl wall spackle that you can buy at any DIY or home center (Lowe's - Home Depot) applied it with a 1" wide flexible putty knife. Then using a home-made tool I created the criss-cross pattern.

The fact that the paste could be easily removed or washed off was a plus. In fact I used it to my advantage to create "damaged" or "chipped" effects to the zimmerit. I had posted a pretty extensive thread on the build as I worked through it, you might find something in it helpful, I had quite a few responses. You can find it under "most active" the title was Panther G rebuild or click the link below if interested.

http://www.rcuniverse.com/forum/m_72...tm.htm#7232225

Here are a few pics of the tool I created as well a a few shots of the Panther. I hope this helps at least a little.

Regards

Craig (Squid)