Does anyone know if there a way to use the MLG/mcmap method with a specific seed instead of random seed?
Create a world in single player with the seed you want, preferably with the name "world" (as it's the default name used for servers). Copy the world's folder into MLG and run MLG. It will use the world you provided to generate a map.
My latency is about 350ms and the only advice I can give is "be smart in combat". Separate mobs from each other, use obstacles, use gravel/sand to suffocate them, use lava/flint and steel, use a bow, learn the hit & run technique, etc. Be aware of what's going on around you and how you can use terrain to your advantage.
Oh yeah, and mobs' rendering location and actual location are often completely different, but over time you'll learn how to predict where they really are.