Aspiring HotS Zerg player:

Hey dude! I was a diamond league random player (never cheesed except for funday mondays :D) with zerg being my primary race when I played ladder in WoL! I haven't started laddering yet because I wanted the MMR system to stabilize before I was placed and also I have just as much fun if not more refining my builds outside of ladder than playing games itself haha

The reason I'm saying this is because I'm probably going to switch back to Zerg as my race for HotS, and a 1base roach timing is going to be one of my primary strategies. I would like to share my findings with you:
At 5:20 - I throw down my first expansion and my first 3 roaches arrive at his base in which case I try to pick off a zealot, stalker, or cannon with good micro

At 5:30 - Burrow research finishes allowing me to heal the roaches that took damage

At 5:45 3 more roaches arrive at the front and I unburrow my first 3 and push. Use burrow micro and try to bait probes; if probes attack I back up, if they dont I take the dominating position in his natural guaranteeing that it dies
At 6:30 I had 5 more roaches arrive at the front making my total 8-11 roaches attacking at any one time (the buffer is for accounting burrowed roaches) and by this point I start droning hard and lair tech while throwing down a spine and evo chamber. The next point of aggression comes at the 11 minute mark where I have hydra roach drops going on in their main or nydus worm with hydra-swarm host to secure my third/fourth and get 2/2 up

So what you mentioned is you have your mamma-core up in time which makes me think you do a gateway first into fast expand with early 2nd gas. If you do this instead of a 2gate expand later 2nd gas; you have 1 zealot, 1 stalker and 1 mothership core at the 5:15 mark. The mothership core doesn't have enough energy for a Photon Overcharge until 5:50 mark which means I am guaranteed to either deal damage (kill the stalker or zealot) or delay your mining time thus delaying your tech.
After looking at all this I then tried to do a fast expand with core and 1 gate 1 robo play to see if fast tech could be viable and found that I would just straight up die or lose a good amount of probes in the defense. Another case I examined was a forge fast expand where they did go forge first and I found there that I needed to either throw down my gateway before expand (depending when scout occurs) or I needed to throw down 2-3 defensive cannons. As zerg here I would just take my third, delay lair tech, drone hard and try to kite buildings without committing fully to aggression. I know I could do this because the 300-450 minerals he is committing to the forge first defense his 2base push will come 1-2 minutes later giving me plenty of time to secure a third and tech up while defending whatever push he throws at me.

So for all of this is I assumed that the toss player scouted my 1-base aggression WELL in advance and is in cross spawning positions on a 4-player map. I still need to come up with 2 more builds and then practice all 5 that I will have before I actually start laddering. I usually have a single 1-base build, 3 2-base centered builds and 1 purely defensive macro-oriented 3 base build

Let me know if you have any questions or comments :)

Much love,