Typing “Ronson Marshall Major” in a search will get his gear on a site hosted by an Australian collector. Some nice pics of the Ziggy tour.

Still no news of Twizza´s head. A SS head will have an impedance range that it is comfortable with (say 8-16) and it is a good idea to stay within. At best, a safety feature will cut the output or, worse, unpleasant things happen. With valves, there is usually a tap on the output transformer which may be fixed at 4ohm (common with Fender) or selectable 4/8/16 (most British designs) although even earlier amps may be 3.5/7/15ohms (close enough to be of no concern) with 100v that is of no use to common guitar drivers.

Best output is achieved by matching the tap to the cab´s overall impedance. According to a useful site, it is perfectly safe to put a 4ohm cab to the 8 or even 16ohm tap but the vice versa less so. A 16ohm cab to the 8ohm tap could cause arcing across the windings of the output transformer. Apparently, Marshalls are more susceptible than Fenders. Whether Partridges, as used in Hiwatts, Sound Cities and Laneys are as risky, I don´t know.

I do play bass through a Marshall set to 8ohm, going to a 16ohm cab. I´ve had no ill effects, but many would prefer not to risk it. If the four drivers are all 8ohm, then a combination of series and parallel wiring is the best course.

Impedence mismatch is ok one way around, but i cant remember which??
i think if your amp impedence output is less than the speaker then its ok, but the other way round and you will kiss your output transformer goodbye, and that can be a very expensive mistake, i dont think this is as critical on SS amps, as Bass says the G12T’s are the obvious choice for metal, ive never liked them much and dont know anyone personaly that does, but then i love the classic rock sound, so i love my greenbacks, and Bass im glade you mentioned the Late Mick Ronson, he is a big influence on my style of playing, i dont think Bowie would be anything without Micks input and creativity, he defined the Ziggy sound, and its interesting to note that when Mick died a couple of years back Mr Bowie was nowhere to be seen at his funeral. Very sad.

Twizza, if you´ll take advice from a bass-playing not-exactly-speaker-expert 😯 …

1) I think Lee´s right. Your amp doesn´t “know” one speaker from another so the T will take it but the H will possibly blow on full. HST, I gather that the 30W handling was very conservative and they can take 50 (no comebacks on me, though 🙂 )
2) If in a metal band, and rich enough, then the full stack with two 4×12″s allows anything you like.
3) Sticking with the single 4×12″, I have read somewhere that a pair of Ts and a pair of vintage 30s is a nice combination of “hair-shirt” and “mohair” response. For metal, though, the quad of Ts might well suit you best.
4) You don´t say whether the head is SS power or valve (forget about the preamp for now). As I (mis)understand it, with SS power, you don´t want the speaker rated too much higher than the amp. If your amp is pushed full on (at 200W 😯 ) and into clipping, then your cab will be seeing a square wave. This is driver murder. With a valve power stage, a 300W cab is no problem; even desirable. Valve amps clip softer, and the cab can capture this. Also, some think (I´m not going to try and argue) that valve amps have a transient attack well in excess of the rated power but sag quickly, whereas an SS will just putout the signal amplified to whatever value the vol knob was set at. It´s some people´s expl of why a valve amp ´seems´ louder than its rating.

I ramble, but maybe some of this is of use. One last thing. Search for the gear used by Mick Ronson (Bowie´s guitarist). He used a 200W Marshal Major head, and his cab setup may be of interest. Finally, Lee mentioned the impedance. Wiring the four speakers up to fit the output impedance of your amp is very important. Done wrong, this can fry all sorts of components. More on this turgid aspect available on request…

ive always been told if you use different speakers in a cab, the total handling capability of that cab is multiplied by the lowest rated speaker, so although your 2 G12T’s can handle 75 watts each the H30’s are rated at 30 watts each, so your cab would handle 4X30 watts =120watts total. Some would say this is OK for a 200 watt head beacause the chances of running your amp anything near 200 watts is pretty remote, unless your name is Lemmy of course, the 2xVintage 30’s and 2xG12T’s would fair a lot better, the vintage 30’s are rated at 60 watts each giving a total of 240 watts for the toalt cab output.
maybe you could pull 2 of the output valves dropping your output to 100watts and put int eh perfect combination 2xGreenbacks (25watts each) and 2x vintage 30’s, somtimes its worth sacrificing volume for tone!!
PS watch your impedence too.