Im not sure what the specs on the factory wheels are, but if you stick with the same width (say 20x9) just subtract 26mm from the stock offset and that will place the wheels out about 1". More or less depending on what you like.
For example if stock your wheels are 20x9 +26 and you want it pushed out 1" find a wheel that is 20x9 with a 0 offset, if you want it out only 1/2 inch find a wheel that is 20x9 +12. If you go with a wider than stock wheel then you will need to adjust accordingly. (20x10 +13 will sit the same a the 20x9 with a 0 offset).
I believe your stock 20s are 9" wide with about +19mm offset and 5.5-5.75" backspacing. Looking at the Dick Cepek website I would assume you are looking at the 20x9 wheel also. So at the same width but with the new offset/backspacing the DC-2 wheels should stick out about 1.25" more than your stockers.
Yes, the factory 20's have a +19mm offset. I recently bought 20x10 wheels with a -12mm offset and they look great. I'm running a 33" by 12.50" tire without any issues.
Mind you, in the pics the tires look close but it's only becuase of the factory runningboard/fender flares drop down 2" from the original fender lip. So I actually lose 2" of clearance at that point. But they will be coming off in the summer time or maybe a suspension lift....