Home gyms are great... I doubt you will hear many people debate that.

That being said I will try to leave as much of your own workout to your own devices. I will simply give you a couple good rules of thumb to go off of. By no means would this be the ONLY way to do things, but I think it makes sense.

Fist off, you need to be worried about strength, though I can appreciate that you are not training for power lifting. Never the less, without continually looking to increase strength, your body will have very little reason to grow. How you measure that gain is up to you. More reps with the same weight, more weight for an equal number of reps, more reps in a defined period of time... etc. Pick the factor that best suits you OR use as many as you feel comfortable with.

As an example, you could try to improve week to week on your 5RM (5 rep max, or the most weight you can lift 5 times). Leg extensions and curls you could see how many reps you can do with 100lbs without taking a break to rest. Once you HAVE to rest, you are done, get one more rep than last week. Weighted lunges you could see how many you can do in five minutes. Rest as much as you need to, just make sure you get at least one more lunge in each consecutive week. Understand?

The truth is that the number of reps and sets is irrelevant. You have to A) stimulate growth and B) recover from your workout. It is that simple. The only way I know of to accomplish "A" is to get stronger. "B" can be tricky, but on your bodypart split I don't see a reason you would be overdoing it.

Lastly I will say that I have personally found it better to concentrate on a few lifts that are important to you than to try to do everything under the sun. Or, as I have also suggested, perhaps it would be wise to follow a pattern like this, for exercise selection:

The first exercise of the day is the one exercise that matters most. The second exercise can come from a small group of exercises you also enjoy, but limit yourself to about three selections. Lastly, pick something related, and it can be ANYTHING you can dream up.

So for chest it might look like this:
1. Bench press
2. Dips, or push ups, or incline bench
3. something that hits the triceps or chest. Doesn't matter what.

To put the two ideas together you get something like this:
1. Bench work up to a new 5RM
2. Dips or Pushups or incline bench (pick a weight and do 1-2 sets for as many reps as you can get, aim for something around 10-20 reps)
3. Something chest or triceps, as many reps as you can get in 3 minutes.

That is it, three exercises. Some consistency in exercises so you can monitor strength gains, some variety so you don't get bored, etc. You will hit top end strength and high rep endurance, and you have some metabolic conditioning built in (google it if you aren't sure what this is).