Unpopular opinion: your raised garden bed doesn't need 12 inches of soil, 8 gets you the same tomatoes
I built two beds side by side in my Sacramento yard, one at 12 inches and one at 8, and after one full summer the 8 inch bed gave me 41 tomatoes vs 38 from the deeper one, so save yourself the $60 in extra dirt and spend it on a drip line instead, anyone else tested this or am I just lucky?
There's a pattern I keep running into where the "standard" advice turns out to be way more than what's actually needed. People online say you need a foot of soil for tomatoes, but tomato roots mostly feed in the top 6 to 8 inches anyway, so the extra dirt is just sitting there not doing much. Same thing happens with mattress shopping, where everyone swears you need to spend a grand, or with cooking gear, where people buy ten knives and use one. We tend to copy what we see others do without stopping to ask what the plant, or the task, really requires. Your side by side test is the kind of thing more people should do instead of just repeating what they read. Spend the savings on water delivery, since that actually reaches the roots.