Yeah, you want to do almost the exact same things to the .25 carb as you do with the .15 carb. The design is actually very simular, just a little bigger. But the low speed and high speed needles look almost exactly the same. (I haven't tried swapping them, but they look awfully close).

I also just finished going through all my Mag .25 and .28's and drilling out and tapping the carb mounting screws to 6-32 instead of the stock 3mm. I only had to do that after nearly 3 years of running them hard. Just be sure to use a good application of locktite on the carb mounting screws, and you should be fine for quite a while. But if you do strip them out, the tapping operation is really easy, and a 6-32 x 1/4" long socket head screw is really an improvement. Oh, last year, I also found that the Ace hardware store near me stocked 3mm philips head screws that were better quality than the stock screws and were easier to get in and out and get tightend down nicely.