has made a very complete timer
for gen 4 and 5 RNG that is very good. The C-Gear timer is especially well done and highly recommended.
Below is how I did C-gear seeds with Pikatimer, but I recommend you use ZomgTimer.
To help out people just starting with C-Gear seeds who may be wondering how to put this together with two stage timers like Pikatimer: I kept Pikatimer at 500 for calibrated (but I didn't calibrate at all) and made sure my given seed allowed at least enough time on the first timer to get the DS started and on the game start screen, and made sure my second timer gave me enough time to then enter the game and wait at the screen to turn on the c-gear.
So as an example, for my RNG on Reshiram on a carte I did this:
My seed was 51d6a103 for a Mac address of D49731. For this seed, I took today's date, Dec 1, 2010. Target time of 2:49:20. Target delay of 2504.
On Pikatimer, I put the calibrated at 500. I chose 15 seconds as my calibrated seconds, but used 20 seconds for my target since this gave me enough leeway on the first timer without wasting my time. I set my DS to 2:48.
Edit: Some notes added Dec 07/2010.
Be prepared to recheck your total change (total delay change) if you resave in front of Reshiram. Resaving may throw off the amount of delay you get. You'll know when you somehow lose track of your possible IV spreads on the adjacents list. If you just can't find a match, suspect that your delay may have jumped up or down by 50 or more. Re-calibrate the necessary delay change by going back to the original timer with no delay changes. Search for a matching adjacent and re-adjust your delay and seconds.
I started the game (from the DS menu screen or the AR game start screen) at the end of the first timer. I said yes to turning on the C-Gear at the end of the second timer. After capturing a few pokes, I ended up adjusting Pikatimer by -309, so it's very important to have your adjacent delay range 999+/-. Put your seconds range at 9+/- just to be on the safe side.
I saw odd and even delays during adjustments but still landed on the even delay. So odd and even doesn't seem to matter.
Edit: I've edited this post multiple times now because I thought I'd remembered my first RNG wrong, but I've just gone through the same process again, catching with the same seed. I was correct in remembering that the large delay adjustment caused a big change to the seconds I landed on when getting into the game.
So here's how it went the first time, and the second, and how I handled this:
Given the above info of seed and delay (500 calibrated/2504 target, 15 seconds calibrated/20 second target), the first time I used a start time of 2:48 on the DS, I landed in the game on the wrong delay but the correct target seconds, which was 20. But I had to adjust by -307 to get the correct delay. When I did the next reset, I discovered myself on 15 seconds but closer to my delay. To compensate for the wrong seconds, I adjusted my DS start time upward to 2:53. I did my final RNG attempt and landed on the right delay and the correct seconds and got my target IVs on the captured pokemon.
So, what I'm saying is that you should be aware that huge delay adjustments require changing your DS clock minutes up or down to compensate for a change in seconds within the game. One minute on the DS corresponds with a second in the game.