Great job! Doesn't it feel rewarding working with your hands, then seeing and enjoying your accomplishment
Tip: Make sure to check coolant level in radiator after 8 hour cool down. Each morning until system will no longer take/needs any coolant added. Engine must first be run up to full OP temp with cabin heaters on full hot and driven at 2000 RPM.

Why the 15W-40 diesel oil. 2UZ-fe gas engine calls for 5W-30. On cold startup the high "W" will increase engine wear!
There's one "dude" on mud touting that viscosity "W" diesel oil or higher. To "validate" his "tout" at the time; he showed ~20MPG from a screen shot of NAV screen. But recently he started a thread, posting up screen shots showing his tracking MPG over about a dozen tankfuls of gas from various vendors. It showed his MPG ~12.5 MPG, which is ~2 MPG below average for his area.
If you live in a desert with temps around 115 f range, you may want a higher viscosity in the summer. But in USA Toyota has now gone to 0W-20 in the 200 series. It improves fuel economy, faster cranking on cold morning start up and reduces cool startup wear.
All 2UZ-fe I use 5W-30 Mobil 1, it's readily available and top shelve. Any good synthetic gasoline engine oil is best choice.