Pictures are definitely worth 1,000 words. I was about to suggest you were trying to make excuses for not just putting down some seed and toughing it out. Now that I see what you're dealing with (river bottom rubble), if you can reschedule and rebudget your lawn, I would drag that stuff out and replace it with anything from sand to screened topsoil, or "landscapers mix". The least expensive way would be to sift your current soil to dispose of the rocks and use that. You can improve your soil from the top. It does not have to have amendments blended in. But I think you need to get rid of at least the larger rocks. You might check into getting a landscaper to give you an estimate on sifting the rocks out. He may want to scrape them out and replace with better soil. That's okay but get an estimate to do it both ways. If you are starting with your same, sifted, soil, then you can get going on fixing it with water, shampoo (to help the water soak in), a little bit of compost on top (NOT TILLED IN), and some organic fertilizer. Mother Nature fixes Her soil from the top. When we try to jump start things, it usually does not work like you expect. Spray some clear shampoo at a rate of at least 3 ounces per 1,000 square feet and immediately scatter the compost and organic fertilizer. Then immediately irrigate another full inch to carry the soap in. Repeat the shampoo again in 2 weeks and your soil will be on its way to recovery. Then irrigate once a week in the summer and once a month in the cool months to keep the soil microbes moist. That should get you going.

A mattock comes in several weights and has about a 36' long handle (for scale). A cousin was saying several weeks ago that because her ankles are so weak, she can't use a shovel even to replant annuals each spring. So we asked her why she hadn't used a mattock...well, there was an easy answer...she'd never heard of a mattock. You stand up, and swing it and it DOES go into soil, even when the soil is hard clay. And it will make a hole when a shovel just won't do. Here is a link that might be useful: Mattock

I thoroughly dislike eucalyptus globulus (blue gum) and acacia mearnsii (black wattle), but that's because they were invasive where I grew up and the pollen from the black wattles was horrible. I've seen people try to grow eucalyptus in Raleigh and it's a dismal sight. Even I feel it borders on abusive to take a tree that should be evergreen and magestically tall and have this poor, half dead, stumpy thing dripping bark in your garden. I'm not crazy about the native pines in the southeast US, because they all have prickly pine cones. I can't walk in my back garden in bare feet because of all the cones from the loblollies and long leafs (long leaves? LOL).

When posting and stuff goes pftd hit the back arrow. Sometimes the post is still there. Alternately before hitting send, highlight and copy to your mouse and hold it there in imagination and then hit send. If all disappears you still have the text hanging on your mouse click to paste into the next message box.