yes, this sort of thing is more for saving money, not making uber fleets. if your attack ships have the best weapons, and most weapons THEY will get targeted and your designated victim ignored. just underweapon your attack ships enough to get your martyrs prioritized or keep old ships running with brand spanking new martyrs and it can work like a charm

and don't forget your martyr has to be competetive with the enemy ships or this tactic will prove totally useless. it's not a magic bullet.
oh, and one more thing. get master hull building and the other hp techs. more hp means you water down your defense on your martyrs, allowing you to put more firepower on your shooters.
10atk4def16hp=.5 priority rating. the coresponding attack ship needs to have LESS than 8 atk to be protected 8atk0def16hp=.5 priority. now, with 25% hp bonus it turns into 10atk4def20hp=.416 priority and your shooter now can have up to 8.3 attack while being protected 8atk0def20hp=.4 priority. so that 4 hp bonus allows you to upgrade your shooters from 7 atk to 8 while being protected.