The recorder you are using is fine for the job. It just needs to work properly. The mics are the most important part of the gear-chain, in combination with how you set them up, and most fundamentally, where. If you can get away with it, increased height above the audience will often help significantly when people are talkative, but be careful not to go so high as to position the microphones above the high-frequency radiation pattern of the PA - it may sound perfect at head height but dull and reverberant above a certain height limit.
[...]walking around and using your ears to find a good sounding spot is a great habit to form. Hopefully you can do it for an opener. If it sounds sweet to your ears, it will probably sound sweet on the recording. Often I find myself close to the soundguy.
^This.
A hierarchy of recording location constraints-
1) What the band will allow you to do.
2) What the venue will allow you to do.
3) What you are comfortable with managing.
4) What the variables involved with the PA setup and mixing dictate.
5) What the acoustics of the room dictate.
My earlier post on optimal recording location suggestions only addresses the last couple entries in the above list.
Regarding my earlier suggestions, don't het hung up about the spacing between mics too much, it's the last thing to worry about, more a "nice to have" icing on the cake and simply the next logical step which follows the more important aspect of making the most of whatever direct-sound/reverberant-ambient-audience-sound ratio you are dealing with (determined in turn by the even more important aspect of recording location) by directing the most-sensitive on-axis part of the microphone's directional pattern toward the primary PA and on-stage sound sources.
Record from where you can get away with doing so, where you are comfortable managing it, and where sounds best, and then if possible configure your rig to make the most of that situation, to whatever extent you are comfortable with.