I prefer to use fast missile ships in the early game
An Escort with max engines and a CSM I is worth its weight in minerals. I have had one single CSM I scout vessel take out over 600kT of enemy scout/combat vessels, 'cause they were armed with short-range DUC's..... I always set my missile scouts to a "Sniper" strategy; Maximum range/Don't get hurt. Works like a charm
Alternatively, if your "Guardians" are meant for WP defence, give them really powerful short-range weaponry (i.e. Ripper Beams),
lots of it. Multiplex Tracking is also handy, if you can spare the room; same goed for Combat Sensors. Don't bother with ECM; unless the enemy sends in an overwhelming force large enough for it to be reasonably battle-worthy after the first round, you won't be bothered with (much) return fire. With any luck, if the enemy fleet is small enough, you can cripple or completely destroy them in a single round.