Mastiffman;
BTW: You got saddles for those pups? I'm thinking you could save on fuel , by building a small chariot and have them pull you to work
Let's step back just a bit and about saving you some up front money.
For now you're wanting the build a 12V system, those panels are 250/ea at 250watts 24Vdc.
Like other say you could buy them and they would certainly workout with future plans to go up to 24V or 48V system.
IS this upgrade in the near or say +5 years from now?
IF it less than say 5 years then I'd say maybe going looking for 12Vdc panels, there's a post to a link for 12Vdc at a lower cost with full warranty.
Then as other have said you would then get full use of all available from each panel.
Also, you could wire in 12Vdc computer muffin fans up at attic vents to push air out. I do, it sure makes a difference on the hot side of our house!! I found a couple battery powered fans with 9" blades. I use a small 7Ahr 12V SLA with a 1.5watt 12Vdc panel to run it each day, when one of us gets home we run the attic fans for about an hour before powering up A/C sure makes a difference!! last months AmerUE bill was lowest June bill in 15 years!! and that's with 10 100+ days.
I'm a happy camper
dog's aren't
'cause they don't get to stay inside with 83degree cooling, but the have the basement where it's NOT 100 and shady
I'd hate to see you buy these then struggle to get max out of them.
Cheers;
Bruce S