Hello LRB people, please can you help me before I make a costly mistake?

I've just purchased a 1970 Martin D28 that was already fitted with a passive iBeam; I love the guitars rich sustain and resonance but I'm not sure the iBeam feels the same way about it.

I play Celtic and Folk music in a loud band environment & feedback has just become a major issue for me. For the past few years I have been using a mid-range Takamine 'workhorse' with regular Fishman active piezo system and have never once had any issues with feedback. The sound though was not to my liking so having always wanted a Martin dread and constantly hearing people praise the natural sound of the LRB iBeam I thought I'd struck lucky when I discovered my D28....plugged it into our rack d.i at the next gig and it was just unusable; thin sounding, the D28 spruce top was hyper-sensitive and very prone to low frequency feedback. No amount of EQ or repositioning of my RCF monitor helped. I'm sadly back to the Takamine while I address the problem.

I've got a para DI on order as I figured it'll help no matter what I choose and I've also just tried a Fishman rare earth humbucker on the D28 but I really dislike soundhole pickups and the 'A' note frequency with the rare earth seems to drive the D28 crazy too.

I'd really like to work with the passive iBeam if I can but I'm slowly gathering that they are not ideal for loud band situations.
My ideal solution would be something that will.....
1) sound good in a loud celtic-rock setting without worry of feedback
2) be visibly discrete and allow me to use a feedback buster in the soundhole if I need to
3) preferably interact well with the para DI and maybe even combine with the passive iBeam too

Sorry for the long first post!