Typical close mic'd IR's contain reflection comb filtering, which the OP has described when he said "boomy and fizzy" etc, so OP, try the Axe's waveform smoothing which is called "DePhase" in my Axe II's Cab Block (Ares 2.x), that might help you as it smooths the peaks and valleys in the freq response cause by the early reflections.
Also, since you are a pro audio guy you might be interested in the Redwirez IR sets which give you a lot of mics and mic positions to choose from and/or mix etc.
Tone Matching is of course another possibility, as are reflection free IR's.
Also, since you are a pro audio guy you might be interested in the Redwirez IR sets which give you a lot of mics and mic positions to choose from and/or mix etc.
Tone Matching is of course another possibility, as are reflection free IR's.