A couple more suggestions for you before you go further:
If your going to go through all of this work and all this effort to build this cabinet and then purchase and set up all this stuff and take all this risk, then make it worth the trouble. I suggest the following:

1 - Make it taller than 5 feet. By the time you take away the space at the bottom for the containers, and then take away the space at the top to hang the lights, and take away the space between the light and the plants for heat dissipation, you will have very, very little room left for flowering plant size. Believe me if you make a cab with 5 ft of total vertical space, you will forever wish you had just made it a little taller. 6 feet min, 7 or more better.

2 - Don't wast your time and money on a 150 watt HID light for flowering. The amount of flower that you will produce will not even be enough to keep yourself in stash. You will run out long before the next set finishes. It's really not worth all this trouble and risk for anything less than a 400 watt halide for your flowering cabinet / space. A 400 HPS would be slightly better, and a 600Watt or higher HPS better yet. I realize someone may disagree, but this is just an honest opinion based on experience. Why go through all this and still not even have a steady supply for personal use.

3. With a cab of that size you describe, you really need a separate veg area. That's barely big enough for a decent flower spot for a couple of plants. Build a second small cab with FLs for a veg spot. On this one you can go with a smaller size cab and high output FLs.