research=good plan. maybe have two 'trees' you can research, something like this...
(' ' is working title, [ ] is RU cost estimate.)
all weapons and systems restrained by research
>base-mass driver cannon, flack cannon, all nose weapons.
>Torpedo launcher - [300-400]
>LC mass diver cannon - [250?]
>Preliminary system assessment (does nothing except unlock next research level) - [580-600]
>Artillery cannon - [400-500]
>Ion cannon - [600-650]
>Scan array miniaturization - unlock nose-slot Advanced sensor array - [800-850]
>Reactor power efficiency improvement - next tier of research unlocked, required for Ion cannon use - 
>HE artillery cannon - [8-900]
>tracking system miniaturization - allows Fire control tower to be built in one of the slots. - 
>Phase systems integration- unlocks final research tier - [1000-1500]
>Tier Four- Advanced systems
>Phase interlocks- 
>improved power relays - 
>Hyperspace core synchronization -  - each unlocks in turn, giving access to the following addinl' researches:
>Hyperspace lockout initiator-allows Hyperspace inhibitor to be built in on non-nose slot. - 
>Hyperspace systems integration-allows Hyperspace module to be constructed in non-nose slot. - 
>Hyperspace monitoring post-allows HS sensor array to be built in non-nose slot. - [1000-1500]
>Electronic warfare systems-allows sensor scrambler in nose slot. - 
also, as there are no additional slots, you must reduce the fighting ability of you configuration to use one.
in other words...
>top- HS sensors
>back- HC MDC
>bottom- ion cannon
or alternately, a EW destroyer-
>advanced sensor array-nose
front HS inhibitor
top fire control tower
rear HS sensors
bottom HS module
no attack here, but still useful as a way to 'slingshot' a group of, say, 6 flack frigates and 8 torp frigates somewhere without reveling the direction your shipyard is hiding in, for example.
or the most obvious-
Front, top down and back HEs, nose Advanced sensor.
but getting there would cost mucho smackers. (I mean, you are talking about retrofitting systems to something half the size of the smallest ship (By volume-vagyr BC) that carries them normally... you'd at least have to overhaul the power plants! (Particularly for Ion cannon... if I remember my lore correctly, those things are major energy hogs. and as long as you're overhauling things, those power relays on deck five have been giving me some trouble, and soon enough, you've got the whole thing disassembled in dry dock and the foreman comes and yells at you to work faster....anyway, costs increase dramatically, meaning to get modules you might not get that fifth BC....