Whatever you do, NEVER mess with wet soil. We ploughed a muddy field 5 years ago, last year i waited till it was dry and cultivated, ripped and then ploughed again. Most of it is better now, but there are still too many bad spots which have standing water in the middle of the summer (even though
we are on beach sand soil, which needs a lot of irrigation to keep it green)
I wouldnt recommend running a subsoiler at 3 to 4 inch spacing, if you have a healthy subsoil all you can do is mess up what nature (worms, bugs, frost/thaw etcetera) has built over years.
I can get an 11 tine (2 meter working width) chisel up to 35 cm deep before i loose traction, which is below ploughing depth. going 2 to 3" below ploughing depth is enough to cure any hard pan generated by a plough.
about ripping, deeper isnt allways better. We have another field which is heavy soil, red iron ore containing soil. There is lots of ore rubble just below the topsoil, on top of bright white sand at 40cm depth. What i do is run the ripper at 50cm depth so the chisels run in the beach sand subsoil, and max shattering effect is created in the soil just above the shank, in the ore.
Best way to reduce compaction i found, is spreading lots and lots of aged straw manure, with lots of worms and bugs. We had a vegetable grower take our horse manure for free, for years. We kept ripping and re seeding this field every 3 years. Until the vegetable grower didnt need our horse muck anymore, and we bought a manure spreader to spread it on our own fields. When applying lots of organic matter on a grass field, lots of bugs and worms go to the surface to work the organic matter down into the soil. This gives a lot of pores in the soil which allows water to drain into the subsoil, and aerates the sod. Since we spread straw muck again we didnt have any problems with water standing on our fields.
There is just one drawback, the worms and bugs that are attracted by the straw muck, also attract lots of moles
