For matches I've started to transition away from using a wrist mounted dope holder and have started using a rifle mounted dope holder. The pros to a rifle mounted set up are that it is easier to switch your focus from looking through the scope with your dominant eye to the dope card with your non-dominant eye when it's mounted farther out and close to level with your eyes. Comparing it to using a wrist coach I've found it easier to see the dope while I was in multiple different positions and that helped reduce my stress level a bit when I'm going from target to target and I want to make sure I'm getting the right dope. When I was using the wrist coach there were times I was in a position and I'd have to break my cheek weld, look down at my dope card, come back into position, apply the corrections, and repeat. I made it work but having the dope at eye level where it's easier to focus on it is great. I don't think there are many downsides to a rifle mounted dope holder, I mean it blocks your view a little bit shooting but the flip side of that, again, is that with the dope holder at basically eye level your non-dominant eye is picking up the dope on the card. Cost is another downside but worth it I think, I know the guys from Hawk Hill, they are fantastic dudes but understand that it's not bias talking when I say that their dope holders are the best on the market in terms of quality and utility.
Something that I've started to copy from a lot of guys is using masking or painters tape to write the dope on. In the past I used index cards and it's a cumbersome solution IMO now that I look back on it. I got a roll of generic masking tape for about $3.00 and that should be enough to last for a long, long time. Add in some Sharpies and you're good to go.