hi, I have the beta, concert, coliseum bass and coliseum 300 models of sunn, so one could say I have the opportunity to compare. IMHO I would say the combination of your gibson LP with a big muff on a coliseum 300 is definitely the heaviest and thickest one, especially when you use .12 or .13 strings and tune them down, to D or even B! even a clean guitar on a coliseum 300 sounds extremely full and warm, but very clean when you do not use a stomp box. I do think they look butt ugly though!
cheers, guy