Apologies - the "tail" section is the part with the two beams (split-neck I believe you're calling it?) - the more solid part towards the right is the prow. Or to put it another way - two decks, tail / three decks, prow. Thrusers located in the large chunk on the underside (note that "notch" cut out of the gray armored bit)
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I'm far from done, however this is what I've got worked out thus far:
-I'll need to add some armor reinforcement along the tail sections, and probably something down the front as well (although I'm not sure, as I want to avoid it becoming too "Deimos-like")
-Top speed I was actually thinking something rather high for a cruiser - around the 30-40m/s mark. Its turning capabilities however, would be something on par with a destroyer. In a PCS sense, that would be copying an Orion's maneuvering code from the tbl's and importing the mass and MOI from... well, atm I'm thinking Deimos, which is about double the Grimalkin's size.
-Weaponry: I'm actually going to try and avoid beams altogether, if I can. Turrets will be a combo of rotating cannons and "buttons" as well as a single "Primary Gun" (actually classed as a missile-bank) mounted in the dorsal structure - something I'm currently calling a "Fission Cannon"
Other armaments will focus mainly towards cap-grade lasers and flak/missile arrays.
-Ramming isn't a "common" tactic, although it's been known to happen. In those instances, two Grimms will usually coordinate and focus on a specific target of corvette or destroyer class and aim for the center. It's quite demoralizing for the opposing fleet to watch one of their big killers fold on itself after getting gut-punched by something half or a quarter of its size...

Not that I could ever recreate that effectively in FS2...

-The tail section contains the mainframes for communication and sensor data (read $sensors and $comm subsys). Would've liked to have $Nav too, but it would be horribly inefficient for the crew to plot courses and subspace routes, etc. with the mainframe at the other end of the ship...