Hi people, the fact is I've allways wanted to play BFG, and now I found how to get models for it

The list I thought of is as follows:
Flagship: Despoiler Battleship (st4 lances, torps, chaos warmaster, CSM crew, terminators) 530
Styx heavy cruiser (chaos champion, CSM crew) 325
3 Murders. 3x170=510
1 Dauntless (lance) 110
1RR. 25
Total 1500
The idea is that te first turns I can deal sone damage with all the lances and the ordnance, and then go in with everything but the styx.
But I've never played so who knows how would that go (hopefully you, that's why I'm asking here

)
You think it's playable at least? I don't wanna go arround winning tournaments, but I'd like my first buy to last some time.
Regarding this, you see the torp upgrade in the Desolator good? It looks nice on paper (2 bays for 9 torps, that might be boarding) but, if course, never actually tryed anything.
And the Murders look better to me as standart, but I'm inerested in the general opinion on the lateral lance option.
Thanks for your time.