Maybe about 1:40
Could do 1:20 but current may still be strong
*If* you have any interest in making yer dive longer, you can enter significantly earlier. The key, though, in my experience, is to limit yourself to the areas straight off the beach, out towards the channel. As you get into water in the ten foot range, the current lessens somewhat - enough so that if you have something to "stab" into the bottom, you can relatively easily hold still. I've done this primarily over on the western side, entering as much as three hours prior to high tide, knowing that I have enough air with me for up to four hours of (shallow) bottom time. There can be plenty of cool stuff to see out that way, especially if you go *very* slowly. And, if you find something cool and hang with it for a while in one spot, it's amazing how often something *else* really cool can show up in yer peripheral vision.
Having said that, if you enter too close to the furthest west area of the beach, next to that first pier, the current will not be nice to you and you'll find yourself heading westerly at a rapid rate. On the other hand, if you can avoid that area and make it out to the deeper, ten to twelve feet deep area, I've taken photos three hours prior to high tide of my rope to my dive flag hanging practically limp.
I'll hang out in the area straight out from the beach (quite a large area) until about an hour before slack high and then let the current help me wander over towards the northwest, checking out the west wall and west of the fishing pier. I can then let the changing current direction help me ease back towards the entry area.
The only time I tried an "extra early" entry on the east side, I also tried "short-cutting" it without first heading south, and found myself in a ridiculously strong current under the east bridge, with me on one side of a bridge pier and my dive flag on the other, both rapidly heading north. Not pretty.
One of the main reasons that I prefer the west to the east side is that the average depth seems to be significantly less in the areas where I hang on the west side. I much prefer a four hour dive to a two hour dive.

Just be sure to dress appropriately for the extra time.
I *did* once experiment with the current direction (incoming, just prior to high) off the beach trying to see where the switch was from "primarily east" to "primarily west". It seemed to switch somewhere in the vicinity of off the lifeguard stand. YMMV