I'd stay with as is.
1) play what you know
2) Plague marines charging out of an assualt boat is meh, your just paying through the nose for a bit of shielding to their role.
3) above 1500 most landraiders become fodder unless you truly spam (I take 9+ fast melta in 1500 above that I start getting serious) Keeping the fire/distraction of 3 ponderous oblits might keep some fire off your assualt boat for a turn (which is all you need).
-Chaos, really suffering. The higher the points brackets the more you can expect someone to pay (IIRC 45 points) for a old style hood to be stuck in their army on top of meching out. Above 1500 but lower than "OMGs I've run out of slots" is a really good place for our opponents to all sit.
BTW me and ljundhammer (due to the GT being crap) are being lured to the maelstrom stuff.. we may start attending these things..keep us informed
E.g. it being "2", did your first fee cover a whole set of events or are they seperate and your just paying for each as they come up?