Having had the boat a few years now, I've taken the mast down and put it back up a fair few times. Firstly to install the roller reefing, then various maintenance tasks such as adding tape to the spreaders to stop (another) rip in the cruising chute. Most of the time I do this by myself these days having developed a bit of a technique over the years so I thought I'd share this "wisdom" with you, the Internet. This is probably not the best way of removing a mast in a tabernacle, but it works for me.
Step one is preparation. This is really, really important as surprises half way through are not fun at all (trust me!). At the stern, I rig a cross to hold the mast. This is little more than two pieces of cheap pine with a big bolt through them. As you can see, these are held in place with various ropes. One to the back of the tiller, which also ties to the traveller bar. This gives fore/aft stability to the wood. Next there is a rope from the top to the cleat on the port and starboard side deck which also then go on to tie the base of the wood to the pushpit in order to stop the bottom sliding about. This hold it fairly strongly in place ready for the mast.
As you'll also see in the picture above, I have taped everything up to the mast. Start this off by undoing the cables for lights and aerial and tape these to the stern side of the mast. A tabernacle makes an excellent scissor and will cut the cables if they are in any way loose. Luckily I found this out as I dropped the mast to replace the cables!
Next, remove the boom completely and bring forward the various lines tied to it. The sheet will come off and stay at the stern, the vang will sit on the coachroof, and the topping lift and lazy jacks come to the mast along with the halyard which will need removing from the main. Tape these to the mast with as little play as you can so that you don't later have ropes all over the place. I used to use electrical tape for this but duck tape (AKA gaffer tape) is much easier and neater as well as being easier to remove later by ripping it. Once you're happy with the ropes, it's on to the rigging.
Loosen all of the rigging screws, making sure to relax the tension all around before fully unscrewing. Although not necessary to loosen gradually first I think it puts less stress on the mast so I prefer to do it this way. Once these are all loose, I also loosen the bolts in the tabernacle. Remember that the top one will stay in while the mast lowers, but needs to be loose to allow movement The bottom one at this point can be loosened almost to the point of nut removal so that just before dropping the mast this is very quick to remove - you'll want to move calmly but quickly at that point so have everything ready.
This is my latest technique. I tie a piece of cord to each rigging wire with a bowline. This then goes through the deck eye and back three times to give me some leverage. I can then tighten it and tie off with some half hitches to stop the rig moving while keeping it ready to drop. This is also much quicker to do after raising than going straight to the screws, and you can pretension the wires before connecting the screws.
Finally, I remove the clevis pin from the forestay under the roller reefing. Here, I tie a rope to the bottom of the roller reefing which is led through the anchor roller and up to the coachroof. I use this rope to gently lower the mast until it's far enough down for me to just hold it. I then remove the cords from all rigging wires and the mast is essentially free standing. It can be helpful to tape the wires to the mast at this point to stop them going in the water if you're doing this on your pontoon/mooring (if you are, bear in mind that side to side movement can cause damage once the mast is free). The lower bolt in the tabernacle is next after putting tension on the rope to the forestay. The design of the tabernacle means you can lean the mast forward and it rests in place, so lean into it while removing the bolt so that it doesn't fall on you. Gently let the rope out and allow the mast to drop, standing near the (closed) hatch while it drops into your waiting arms. The further back you are the better your mechanical advantage for holding it up so don't be too close to the mast foot when doing this. You do, however, need to be on the coach roof since the rope won't be sufficient to hold the mast past a certain angle. Many use a pole in front of the mast to add leverage here but for me it's more effort than it's worth. Once the mast is in your hands, gently lower it to the wooden cross. This needs to be tall enough that you can easily lower into it from the roof as you don't want to be stepping down from the roof while holding the mast - trust me!
Tape the roller reefing to the front edge of the mast at this point to prevent damage to it, they bend easily and worse, get in the way while moving the mast. At this point you can remove the top tabernacle bolt.
Now it's just tidying up to do. Pick the mast up and slide it forward. You'll want to be near the middle of the mast for this part so it balances unless you have help. The base of the mast can slide through below the pulpit and stay sitting on the wooden cross.
Raising is simply the opposite to lowering :)