Can I use equations to drive a linear sketch patte

Another newbie 2 part question.

1. I want to drive a linear sketch pattern spacing with an equation. I am not able to add a basic equation in the spacing dialog box (something like =5+1). Is there a way to do this?

2a. I want to drive the number of pattern instances by a predefined variable (=NumberOfBeams) but the dialog box only allows for numerical values. Is there a way to do this?

2b. Bonus question - Is there a way to predefine a set number pattern instances using a dropdown list (15, 18, 21 etc...) and select that during pattern creation? That would be super helpful.

Based on what I have found I think I am going to have to create a design table to do all of this? I was really hoping to handle it all in the "Equations, Global Variables, and Dimensions" dialog box.

Thanks,