Scorp fan, you're right. I uses Marshall JCM 800 2203 model, from 86 year, i always tought about this head, a 85 model, but i did a deep revision this Feb, and i saw a factory quality control sticker, from Jan/86. 85 models have better transformers. I'm not worry, Marshalls have the tone. This head have modified pre-amp. Now i have enough overdrive for play true metal. Zakk uses a Boss OD1 overdrive, i don't uses it. I uses a master reductor for play rhythm/solos. The control knob is in rear pannel, i don't want ruine the look of this head. I also added a FX loop. I did this modification, and "muscle" pre-amp in 1997. 800 2203 model, hadn't these things. Zakk 2203 model, have a FX loop too. Zakk model is a re-edition of older model, maybe 82 model. Older 2203 have vertical inputs. Since 1985, have horizontal inputs. A great difference is the tubes. Mine has EL34 (European tubes) and Zakk model uses 6550 (American). This amps are extremely loud. I uses too 2 cabinets, for bigger sound. This is our common equipment.
I uses an Alesis unit for Delays. He uses different stuff. He uses Cry Baby wha. I uses Mu-Tron wha. I prefer Mu-Tron, cos have longer range. Santana uses it, and used like EQ control is outstanding. Zakk uses the wha in similar way.
I plays with Explorers, and a Robin Medley Standard. Robin has clearest sound than Explorers. For record, have better tone for rhythm, warm and clear, but for solos, i love Explorers. Have a aggresive output, and very heavy tone. You can play fat notes, with great body. And the fingerboard is very comfortable. In this field, Explorer beat to Les Pauls,playing in high frets. Type of fret helps too, i prefer Exporer frets. Robin uses DiMarzio DP 155 model pickups (ToneZone). I prefer this to PJ Marx models. Explorer uses Gibson 490 neck/500T bridge pickups. Sound very similar to Zakk. Maybe the key is in the amp, a good guitar, and THE HANDS. The hands are the "secret" of a player.
Zakk plays with an awesome model, his own Les Paul custom. Maybe the ZW Custom have a little hard fingerboard for play, but sounds giant. I dislikes EMG pick ups..but this Custom with 81/85 EMG's sounds like a hell guitar...is incredible. I enjoyed a lot with this beast. This guitar roars from the hell, screaming in 8 loudspeakers..a great experience.