Faster in the water?

Tonight was the first chance I've had to practice last week's suggestions by Lena on my swim stroke. The 2 things I wanted to work on were a wider and earlier arm entry and a deeper catch. I met Chris at the pool too and I thought that one of us had our times screwed up because he was doing the triathlon swim sessions and I was there for lane swim. Apparently we were sharing the pool and I thought this would be a problem because their group had quite a few people and lane swim was always kind of busy. As it turned out they ended up with 2 single lanes and the lane swim ended up with 2 double lanes. I was in a group of 8 swimmers in our lane and that messed up my plans timing wise. Most of the other swimmers were faster than me so first off I had to pick up my pace in order to not clog up the lane which tired me out quicker so I had to take breaks where normally I'd swim right through the full session. Secondly, every time I reached a wall I'd check to see if one of the faster swimmers was behind me and if they were I'd stop and let them pass so I didn't hold them up. So I tried working on what Lena told me to but I couldn't tell if it made any difference in my time. To be honest, at this point I'm not sure I'll be gaining much time in my swim anyway so I'll just continue to work an these few changes and work on the rest over the winter/spring.