Good morning!
If I were you, I would aim at doing 3/4 of your training on the 152 and 1/4 on the 172. They are very similar to fly, but the 152 is lighter and less stable, so that you must "work harder" to keep it straight and level which is better for developing flying skills. The 172 time is useful too, because it belongs to the category of aeroplanes that most pilots are going to fly once they gain their license.
Greetings, Max