Cylinder Head decision
I may be reading this wrong, but it seams like you just want her back on the road at this point?
If it was me, I'd do a local/cheap cleanup of the original heads, do another 6900 cam.....only break it in properly this time :banghead:, and run the "wee' out of that tired 318, as long as it will last.
You can always put together a "tight" engine build down the road that will fit your usage and budget.
Keep in mind, a good exhaust, intake, and carb upgrade, will give you way more performance then a few 10ths of compression with new/shaved heads...