ok, for those who want help with swarmers, first off, right now it may not be to good an idea, as swarm bonus, necessary to make a good swarmer, has been cut down drastically. so if you want a good design, you will have to make it larger then average, as in I suggest nothing less then 500 space.
1: every credit counts. make sure that no system costs more then 10 credits max, 1 is best.
2: don't forget accuracy. keeping it at 1% may look good on it's base attack, but it makes it next to worthless in actual combat, especially against well designed ships.
3: defense, defense, defense. unlike superships, which use extremely high HP to take no losses, the only way to take no losses with swarmers is defense. the reason is that the defense is taken as a group fleet defense, or the defense times how many ships you have, and no damage at all will be taken unless the enemy does more damage then that fleet defense. thois defense is further helped by it increasing from swarm bonus.
4: sheilds, optional, but helpful. sheilds can help a lot, but will also make it much more costly, making it unpractical for VERY small ships (like less then 10k credits ships) however, if you are making relativiely large swarmers, such as I have advised, it is good to put in 2-3 sheilds to help lessen damage further. but make sure it is off of excess resources, not the main thing of the ship. IE: even 99% Sheild won't help at all if you can only withstand 100 damage.
there you go, everything else you will have to figure out on your own