First of all, if you don't mind somewhat larger capsules, I would consider getting these instead
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-CMC-4UThe 853's are plenty small enough for me to stealth with, you save $60, and most important in a recent head to head comparison test done on this board between 853's and 943's, everyone who had a preference preferred the sound of the 853's. You could also consider the Church Audio options mentioned in my last paragraph.
Whichever you choose, you will want a battery box which will run at least 500 hours on a 9 volt battery (so you can go line in when recording in loud sound pressure situations and so you will get the full dynamic range the mics offer). You definitely need to be able to line in with the H2 when recording a very loud show-mic in will distort fairly easily. You don't really need the bass roll off-most here feel it's better to remove excess bass in post (if you filter out too much bass when making the recording, it can never be recovered).
You'll also want to add the low sensitivity option with either of these mics.
In general, the cardiod caps are better when you are not close to the stage or stacks, if the sound of the room is not good, or if you want to pick up less of the crowd noise behind you. The omni's are a good choice in good sounding rooms or when close to the source. It never hurts to have both (the SP mics have interchangeable caps, so you don't need to buy 2 complete mics). Also some people here have reported good experiences using hypercardiods in situations where cards are normally used, but I haven't done that myself (have only used hypers when very far away from the source).
For running external mics, the H2 was not a particularly good choice, but it should make fine sounding recordings in most situations. If recording something very loud and you need to set the record levels below 100 (with the sensitivity set to L) to keep the meters from hitting 0 dB, your recording will be clipped because the level control comes after the DAC. If this happens you have 2 choices. Move away from the source until the meters are peaking below 0 dB with the level set to 100 or put an attenuator between the battery box and recorder.
http://www.midi-store.com/M-Audio-MicroTrack-10db-Pad-attenuator-p-17305.htmlInstead of the attenuator & battery box you could get a Church Audio ST-9100 preamp which provides 9 volts to the mics and will attenuate as well as amplify. That'd be my choice.
http://taperssection.com/index.php/topic,79928.0.htmlFree shipping this month. And if you've decided you don't need mics as small as the AT943, you could save even more money by buying your mics from Chris Church as well. You can get either the CA-14 cards or omni's for $99 with free shipping this month or get them in a package with the ST-9100. They are great mics, comparable to the SP ones, much cheaper, and you don't need to pay extra for low sensitivity. Only downside is they don't have interchangeable caps (his ST-11's do and also sound great, but sound wise they are not quite on the level of his ST-14's).