Price by Attributes

I have a product that will be priced by attributes. One attribute is size, and the other is wood.

Size I have figured out, but my problem is that some woods we mark up a percentage of the total price (base price + size) and I'm not sure how to do that or if it's even possible.

For example, a piece that we make is 20.00
The size attribute adjusts for price for larger sizes, so for example, 1 1/2" would be +$20.00
From there, I'd like the wood attribute to adjust for a 50% increase on the total price for certain woods. So far, I've figured out how to do a percentage increase, but increases the base price, not the total price. In this case, the total price would be 50.00 (20+50%) +20, when it should actually be 60.00 (20+20)+50%

Is this possible to do, or do I need to do seperate items for these more expensive pieces?

Unfortunately, dependent attributes are not currently available in Zen Cart core code. It should be possible to custom code for what you want, but that would not be a beginner project.
Your best bet is to make the products separate as you suggest, organized by whichever factor you think works best.

thanks! I'm probably not up to custom code yet, and time is a factor in getting this online as well, so looks like I'll list them seperately!