I'm not hugely experienced with shields so I don't know the recharge rate, but you have quite a lot of shielding. Should be extremely effective.
e: Laser is considerably better in terms of range. You still need to catch people in most fleet fights but it should work fine defensively, especially if you order it to begin pursuit as soon as the hostiles start moving.
That's actually very, very little shielding. The format IIRC is [shield strength]-[shield recharge rate]. The 42-450 means that the ship has a total of 42 points of shields--that is, the shields at full will soak 42 points of damage before they go down, which is absolute rubbish--and that the shields will recharge 450 strength every 300 seconds (or 7.5 points each 5-second tick). Basically they'll charge from naught to full in 28 seconds, but only a couple of hits will bring them down. There's no point using shields unless you use them en masse.
By way of comparison, that battleship class I was using to clear out invaders had 500-300 shields (that is to say, 500 points of shield strength) and those
still got mauled pretty badly.
Admittedly it's a tad confusing because the internal format for the shields is [shieldname/strength][recharge time][fuel consumption], so for example you'll design something called a "Theta R240/240 Shield", but what that actually means is that each shield provides Theta-level protection (4 points; they scale by 0.5 per level from Alpha-Epsilon and then start increasing by 1 per level), takes 240s to recharge, and costs 240 liters of fuel each day you have it active. Then, if you add five of those to a ship, you've got a total of 20 points of protection.