I don't often debate with creationists who take a strictly old Earth view yet deny evolution. I did, however, find that I once gave a description of what the fossil record tells us about an OEC type God, so here it is.
If God created each species individually then He did so in a stop-start manner which spanned 4 billion years. He spent 2,000,000,000 years simply creating different types of bacteria. Then, 1,800,000,000 years ago He stepped in to make a eukaryote (despite the fact that endosymbiosis by natural means was capable). Over 600 million years ago, after lots of different eukaryotes being created, He then stepped in to make some simple multicellular animals (despite the fact that this is possible by natural means). At the start of the Cambrian, God started experimenting with hard parts, making very simple shelly creatures and some simple soft bodied creatures along side (showing the proficiency of a beginner, finally). By the mid-Cambrian He had sped up, creating creatures which appeared to be primitive, basal versions of modern phyla. He had finally made proper limbs and proper eyes with complex hard parts too. For roughly a hundred million years God made only sea creatures, before deciding to put some insects on land, making sure they closely resembled those in the sea.
Shortly after, He started creating vertebrates on the land too, but at first He made sure they were amphibious and resembled many of the lobe finned fish already in the sea. He gradually made these tetrapods less dependent on water (shall I jump in now to add that whilst creating these individual species He was also destroying the old ones? Such a wasteful process killed off over 99% of the life that has ever existed, most of which never left fossils). He started creating features like water proof skin, more efficient lungs, waterproof eggs, but gradually of course, He wouldn't want them to look like they were actually created individually. He made sure that they closely resembled other species which would fool us into thinking they were more primitive.
If we jump to around 200 million years ago we find that He likes reptiles. He makes some into variations which go on to dominate the earth for over 100 million years (we call them dinosaurs). He created many varieties of them, always making sure there were forms which were hard to classify due to similar traits (intermediate you might say). In the shadows of dinosaur hegemony, a smaller, possibly nocturnal reptile had been designed. He started making some with a new theme. The gradual changes He included were a gradually more specialised and versatile dentition; changes to the jaw bone, allowing Him to specially create the inner ear bones, gradually; He invented fur and let them make use of it; He created special glands for feeding young; He eventually made them give live birth, crazy guy!
Continuing this theme of creating and destroying, but always with gradual 'advances' He eventually made primates. He liked these and made them into many different species. He always made ones which would look more 'advanced' than the last, especially in brain capacity. Finally, a couple of hundred thousand years ago, He finally managed to make sentient beings. Well, all this is according to the fossil record.