Ampeg Cab Combinations - Advice Needed Please

OK, so it's upgrade time down my way and mighty exciting it is. I'm looking for advice on cabs to go with an Ampeg SVT 3Pro or SVT 450 (haven't decided which yet). Anyway, the question:

I already own an Ampeg Classic 2x10 (250w, 8 ohms) so was going to pair it with an Ampeg Classic 1x15 (200w, 8ohms) for the big bottom. Or, should I bin this idea and just get a Classic 4x10 enclosure..? I've never used a 4x10 cab before so not sure how different it will sound to a 1x15 and a 2x10 which is what I am used to.

I play a Musicman Stingray and like a very big, warm bass sound without too much treble. Quite partial to a soupcon of distortion too.

Any recommendation or advice would be much appreciated.

JW