Swapping out pups from a hollow bodied guitar with no back plate or pickguard can be a pretty nasty feat. The only acces you will have to work with will be the F - holes and the pickup cavity. I picked up a set of un-potted Seymour Duncan Seth Lovers and had it installed into my Gretsch G5122DC. The tough issue here is not the soldering and wiring but more on how the pups, pots and switches have to be coaxed back into place with very limited access.
Here are some key tools that i used.
1. Soldering Iron
2. Soldering lead
3. Musking tape
4. Marker pen
5. Rubber tubes
I'll skip the soldering part. Google "soldering" for more info. The secret weapon here is the rubber tubes. These tubes are used for fish tank air pumps and they are cheap. About $1 per meter from your neighbourhood aquarium store. I used 4 meters of it to have the job done. These tubes will help you pull those pots and switches into place.
Firstly, strip the guitar of any hardware that may be in the way of the job. mark out your bridge position with musking tape so you wont have to re-intonate your guitar from scratch when you are done.
The entire wiring has to be pulled out of the guitar. Do this carefully and make sure that you do not scratch your guitar in the process. always put a piece of cloth on the guitar to protect it if you are working on the guitar surface.
Once the insides are out, un-solder the old pups and solder the new ones in. Make sure you test to make sure that the pups, pots and switches are all working. You can do this by plugging your into into your amp and use a screwdriver to tap on the pups and go through all the pots and switches. If everything is good, use a musking tape to label the pots (e.g neck, bridge , tone1, tone 2).
Now comes the tedious task. Pull the tubes through the pot holes on the guitar and pull it out through the bridge cavity. Cut out the access tube and label it according to the pot hole. Do this for rest of the cavities and your guitar wil look like frankenstein on the operating table. Like this!
Now you can start pulling the pots and switches into place. Attach all the pots to the tubes with the right labels. Make sure you put in the washers for the pots before attaching the tubes. it should look something like this.
Once all the switches and pots have been attached, slowly and very carefully pull the other end of the tube and guide the pots and switches into the guitar through the bridge cavity. The pots should pop into place once they hit the end. Once all the pots and switches are in place, lock them down by screwing the washers and nuts back on. Remember to have your grounding cable in place and soldered if necessary. My grounding cable is attached to my bigsby bar so i had to pull it through with a wire.
Now, all is left is to assemble all the knobs, switches and pups into place. This should not be too difficult. Always remember what goes where, Draw out a diagram of your wiring if you need to. Last thing you need is having to yank out everything because you missed out something or have a pot in the wrong position.
And here it is! the final product! It just saved me some major pups swap money to be paid to a guitar tech. With that money i just saved, I could buy myself something nice. Maybe a new stomp box! Pup swapping on a hollow bodied guitar is NO minor task. It's really not about how you know your wiring or your soldering skills. You really need patience to get this kinda job right.
Total cost to have the pickups swapped minus the cost of the pups and the existing tools i already own ...