I'm switching to the Carvin Legacy head and I'm having difficulty deciding on the cab.
The regular cab for the Legacy has 4 Celestion Vintage 30's and costs $619.00.
I can get a custom Avatar Cab for $537.00 with whatever speakers I want. obviously saving pennies on any purchase is a good thing but:

1) Would an Avatar with 4 Vintage 30's sound the same as the Legacy cab?

2) Would it be better to get a cab with 2 Vintage 30's and 2 12H30s?

The music style is NWOBHM esque mixing into prog, but I also do tons of clean stuff.
The axe's are all Equipped with Dimarzio's and EMG's except for the Strat, that's stock and used for cleans.
Out here you've gotta know where your towel is!
Do you already have the Legacy head? The Legacy is a lead players amp - warm, glassy cleans with a dark, smooth lead channel. It really isn't much of a rhythm players amp, at least not when loaded with EL34's. You might want to check out the V3. The Legacy can do metal, but more along the lines of 80's metal. What type of prog. rock/metal are you going to be playing?
I am the lead player and the metal tones I'm using are very Iron Maiden like but smoother tones and alot of leads going on. (Not willy nilly like DF but tastily placed) I checked sound bytes of both the Legacy and the V3 and the Legacy is really the tone I'm looking for. I don't have it yet, I'm ordering it in a week or so. I am rather sold on the head it's just the cab issue I'm having at the moment.
Out here you've gotta know where your towel is!