Let me try to help you,
I actually do use a BPPC card that i upgraded myself from a 040 to 060 processor. In fact, i used to have a Blizzard 1260, and a BPPC 040, so i upgraded the BPPC and downgraded the 1260.
1. If you have sure that your 060 processor is working fine, there's no need to put a socket for it. In fact the socket, as time passes, will only add to the bad contact probability. Soldering the 060 on the board is piece of cake, so you don't have to worry about heat, of course, as long as you have some soldering experience. If you've never dessoldered fragile components before, give this task to someone that is more experienced than you. Aplying too much heat while dessoldering the 040, will at least mess up the board.
Another important thing is to pay attention to the little plastic pieces, that keep the processor a little far from the board. You need to move them to the 060. The processor dissipates heat from below it's body, and you can damage the board if it's very close to it.
2. You can do the flashing of the card before you change the processors, as well you can do it after the procedure. I did mine after i changed the processors. The board works. You can boot into workbench. But as the library (68040.library in the 040 board) is in the flashrom, you'll lose eficiency, and will experiment some lockups running a processor other than a 040. But you can do it after the processor change.
3. This resistor is the clock divider ratio. In one position it divides the oscilator frequency by 2 to feed the 040 processor. In the oposite position the clock will be sent directly to a 060, so you can use a 50MHz oscilator.
4. Sorry, no screenshots. But if you are able to do the job, you'll have a multimeter and know how to use it.
The part you have to move is not a resistor. It's a miniature coil. It's a black square piece. You can see in a close look that this part is soldered in two pads on the board, and that there's another pad beside the coil. You just have to move the coil so it sits in the same middle pad, and the free one. But before, you can use your multimeter to have sure the free pad haves 3.3V.
By the way, it's not under the processor. It's in the same line as the multiplier resistors.
5. If you did what i said, it sure is !
Regards,
Marcelo.
