No, stick to your original plan, you should grow very well at 375mg a week, just be patient. Shooting every 4 days, bumps it up to 500mg a week which is too much for a first cycle.
Liquidex is a bootleg arimidex... so arimidex by astra zeneca is the real deal and liquidex is the same active ingredient anastrozole suspended in liquid form at a much lower price.
Personnally, I use the liquidex because I can't afford the arimidex(7 bucks a pill or something similar)