On weight, the fluffy bits of trees generally weigh less than tree blokes think. And you still underestimated it. Not by much but you still came down on the wrong side so get out of that habit. Be wrong the other way. This should be your main wake up call. You haven't built, "What if I'm wrong?" into your strategy. You need to or you'll break something expensive and look a twat. Worse, you'll be a twat.
Small pieces = small problems. I've rigged the world and in your example, I'd have still gone a few feet higher and done it in three or four piffling pieces. Those pieces could have been slung up so you cut and catch one, see how the rigging point feels, cut another, make sure it's still OK and so on. You can do things like bundle a few up and lower them in a loop, then pull the loop through and have your rope back. No-groundsman tactics.
If you had to to take it in one, you should have involved the main stem to strengthen the final rigging point. I generally look for a main point in strong, central wood and a redirect over the best drop zone. You'll find those points in honestly 95% of trees. You were basically only using the redirect point. Weak without the context of a main point.
Your current learning style reminds me of me. I got by on wit and feel and I got by well but what I didn't do was engage in the analytical and theoretical learning early enough. If I'd devoted some effort to the stuff that looks like bollocksy compliance from the get go, I'd have got better, faster. MBL, WLL etc is more than just bollocksy compliance. It's real and important. And it's also pretty easy once you decide to learn it. Now is a great time to decide to make your rigging decisions unimpeachable.
If you work by yourself, you're going to have to learn some natural crotch (and other up-tree friction tricks). You should learn it anyway. It's a key skill. The rope for natural crotch is 3 strand. Get some of that first. Owning a length of 16mm double braid without the rest of the skill, people and ancillary gear to utilise it is just spending £150 to look like a billy big bollocks tree man with a heavy rope bag.