Basically, any kind of Orange amp will do I reckon. Post Metal, Sludge, Doom, Drone etc., a lot of Orange gets used by a lot of bands of those genres. Cult of Luna being avid users of Orange not to mention a load of Doom and Drone acts.
Personally, I play those myself most of the time, Sludge/Doom/Drone etc., Cult of Luna, Russian Circles, Sleep, Sunn O))), Earth, Subrosa and the like. When I went with Orange (still not sure why I took so long to go Orange) I had several choices, those were a Rockerverb 50 MKII 2x12 combo, a package deal of a Rockerverb 50 MKII head and 2x12 open back cab - both of those amps were going very cheap as they've been discontinued with the MKIII now in production and the combo was going silly cheap because of that reason and it was an ex-demo too, others were the CR120H head with a 2x12 open back cab or the CRPRO412 compact cab and the CR120C 2x12 combo. I had the budget to get any of those but I had to narrow them down to two... Because I take ages in choosing when there's a lot on the table and before I know it they're gone or the deals are off.
I narrowed them down to two, the Rockerverb 50 MKII 2x12 combo and the CR120C 2x12 combo. I was 90% sold on the MKII simply because of 'what it was' and because of the discount price I got offered with it being an ex-demo, I played it a lot in the store alongside the CR120C but, it was missing something, for my own personal taste and sound, I felt that the CR120C was producing the sound more to what I was looking for than the MKII was - I just felt more drawn towards the CR120C, to me it sounds more "vintage" which I guess is down to Orange basing it on '70s Solid State technology yet also basing it off of the MKII, but that's not to say the MKII isn't capable of such sounds, it is, just that for me I prefer those sounds through a CR120C... If that makes any sense?... Anyway, the CR120C is a monster, well built - like a bunker, solid, reliable, properly capable and insanely loud and the louder it gets the better it sounds which can be quite rare for a Solid State amplifier. I'll never regret making this choice over the other Oranges I had as options, however those are great, especially for those kinds of genres.
With regards to your guitar? Whatever you think really, if you can get those tones you're looking for out of it then that's all that matters. You'd be hard pressed to find a Doom/Drone/Sludge/Post guitarist using a pointy-silly looking Dimebag 'what's his face' blah thing with silly high output pick-ups from EMG through a mega-high gain Mesa-blah-Boogie with more tubes than it really needs via several mega high gain pre-amp/power overdrive pedals anyway. Those genres isn't really about that despite sounding insanely heavy themselves.
My guitar is just a MIM Fender Telecaster '72 Deluxe, Les Paul style layout with regards to pick-ups, controls and 3-way switch. Fitted Ernie Ball Cobalts to it, 62. 52. 42. 30w. 17. 13. strings, Drop B - EADGB, very heavy sounding guitar. Although it's getting modified in the coming months with The Creamery 'Extra Width' Wide-Range pick-ups which aren't particularly high-output, IIRC 11.8k on the bridge and 10.9k on the neck, 500k Bournes/Seymour Duncan pots with Orange .22 drops and an enclosed 3-way switch... Open-geared Hipshot tuners, a Fender Strat style hardtail bridge... Brass nut. Simply put, don't really need to go for a guitar that's held in a specific genre, and if you want to mod it it doesn't have to be with things associated with specific genres, too.
If I may mention pedals, you can get quite a few that are made for such sounds you're looking for. Dunn Effects Pedals (formerly Dunn O)))... I guess you can guess what styles those are), Electrical Audio Experiments - they've just released a pedal called the Model feT of which I'm getting, basically a Sunn Model T pre-amp in pedal form. Even Earthquaker Devices are getting in on the Drone, Doom & Sludge side with a pedal called the Acapulca Gold. One control, Master Volume, and one on/off switch and apparently it's power amp distortion/fuzz pedal that's based on a fully cranked Sunn Model T that's about the break, meaning blow up. Now that'll be something! That is currently on my waiting list, just waiting for it to be officially released which is any day now, can't wait. Pedals like that that can help you find the tones you're looking for, plug them into any Orange amp and you're onto a winner.