Wow - A lot of bad information here.

Probably the best advice here is to get an electrician to do this for you because, while you are on the right track, you show a basic lack of understanding of how electricity works. Here are a few facts to consider, and then perhaps you will see why it's best to get someone who knows what they are doing to help you with this project.

I won't insult your intelligence by asking why you want 240V outlets. If you want it, you want it and the only question is how to get it.

1) In the USA, 240V electricity is actually two, 120V lines, each from a different side of the phase. Connecting these two lines together doesn't give you 240V, it merely trips the circuit breaker. The two 120V lines are fed into an appliance as two distinct 120V lines.

2) The circuit breaker you are referring to may or may not work. Most likely it will, unless it's a slim-line breaker. Do you know how to tell the difference? It has to be a double breaker that connects to both of the bars in the panel.

3) Your drawing indicates haphazard connections. All Electrical connections are made inside a box, not just anywhere you please. Run all your wires, inside conduit, to the timer; use the timer as a junction box then run conduit to your other connections.

4) Your drawing lacks both neutral and ground wires. While a 240V appliance does not necessarily need a neutral wire, all 120V circuits need a neutral to function. Also, many 240V appliances have lower voltage circuitry inside that require a neutral wire. The ground wire is a safety feature.

This is really a very simple application if you know what you are doing. If you don't know what you are doing, you will waste a lot of time and money doing it wrong, then more time and money to have it done right.