Optimum Window Size

Given the following network:

And assuming I am sending you $1000$ byte packets,

And assuming ACKs consist of $100$ bytes,

What is the optimum number of packets you should have in flight at any one time?

Note: Under optimum conditions, you should receive an ACK just after sending your last possible in$-$flight packet. For example, if you concluded that $3$ packets inflight at a time is optimal, your transmissions should look like this:

To get credit for this, you must show how you came up with your answer, and your answer must include the following:

$1.$ Store time: How long does it takes a device to clock the packet in once the first bit arrives at the device.

$2.$ Forward time: How long the packet remains in a router$$s buffer because of packets that arrived before the one in question. If a router contained $3$ packets before packet X arrived, the three packets have to be sent out before X can be sent out. This is the forward time.

$3.$ You can ignore wire time $$ how long it takes a bit to traverse the wire. You$$d need to know wire length in order to compute this.

$4.$ You can assume all the devices are full$-$duplex: They can transmit and receive on each wire at the same time.