Dollar wise and pound foolish to keep replacing parts that you break. The 12 is not significantly stronger than a 10, if at all. If you plan on beating it hard (and you apparently do) then be careful now until you can replace.
Since you've got something that works for the moment, just save up your money, and keep your eyes out for a good deal on a 6 lug 14SF, maybe another front 10 bolt if the gearing is different. Obviously important to know what you've got before you start buying stuff! But no worries about changing the wheels, the brakes fit, and you've apparently got the tools to change the perches and shock mounts. With a lift, slip yoke driveshaft (assuming that) you can probably afford to "decrease" driveline length by the approximate 1" the 14SF takes up.
I think you'll do better finding a 14sf being sold by private individuals, craigslist, thrifty nickel, whatever you've got for cheap/free parts for sale listing, and if you become a member here, post up in the parts wanted section and watch the parts for sale section. Look at the '88+ 1/2 and 3/4 ton C/K (not our bodystyle) trucks. Our local wrecking yards, after pushing the "cheap" ones out of business (or was it the state imposing expensive mitigation projects on autowreckers?) are now super expensive for even the most common axles, generally around $3-500 even for a 10 bolt truck rear, when they are worth about $50.
It's my opinion, but it will save you money in the long run if you intend to run hard and keep the rig for awhile. Spend the money up front, (or save up to get good parts) don't nickel and dime yourself over the years.
My friend has run 12 bolts for years and never really had a problem with them until now, but all the time looking for a 6 lug 14SF. I found one from a member on here, which is now in the process of being put under his truck. I think he may have paid around $250 for it, and didn't have to change anything on his truck to run it, (correct gear ratio) just some time and gas to go get it.
If he has access to a welder, then he can simply get one out from under a NBS truck and move the perches and shock mounts like I did. Maybe his shop teacher will let him use the equipment 
you will be good to go 
. FWIW, I paid $140 for mine, which includes a stupid core charge that they like to tack on. You shouldn't have a problem scoring one for under $200, and the only other things you will need to install it (besides moving the perches if necessary, of course) are a conversion u-joint, brake shoes (unless the ones on the new rear are good) and possibly a new brake hose. Definitely cheaper than buying new wheels, converting the front to 8 lugs, etc.
