Hello Patrick.
I too was once the owner of the Freedom 33 that Pete mentioned, and I had the masts lifted out for painting and to attach new fittings at the top for mounting aerials, lights and wind vane, and also to provide a seal against rainwater ingress, to replace the decaying blob of silicone round the emerging cables.
The engineer in me baulked at the forces the crane would need to exert to drag out the pre-formed wedging rings at the partners, especially as the lifting strop must of necessity be applied to the side of the mast, resulting in all kinds of unintended stresses, crushing forces and bending moments. I opted to remove the wedge rings beforehand, using a short length (1' / 300mm) of wood (I think mine was beech, probably reclaimed from an old piece of furniture) and a heavy hammer. Starting at each side of the split in the ring, and hammering from below, it was reasonably awkward, and took quite some effort to make a start. I had to be careful not to bruise the carbon fibre masts, but a scrap piece of thin ply would help, although that would require an assistant, as both your hands will be needed for the hammer and the wooden drift.
Once the aluminium deck ring is unbolted it can be tied or taped to the mast a bit higher up, to stop it clanking about during mast lifting, and once the masts are out it can be slid off the mast if needed, say for mast painting.
During the lift of one of the masts the crane struggled despite having removed the wedge ring, and I found that some filled resin had been used at the foot of the mast to close up a gap between the circular mast and the aluminium base ring it sat in, presumably to prevent the mast "working" and making noise when the sails are exerting loads higher up. To free this I used a narrow flat bladed screw driver as a chisel, and hammered this in to chip the resin in the gap. As the crane was still under load there was no doubt when the mast became free !
On remounting the masts I used butyl tape under the aluminium deck ring and especially round the bolts holding it down, and subsequently re-created the waterproof boot I had inherited. This a rigid construction made using glass ribbon and resin bonded onto the mast for say 50mm above the aluminium ring, and splaying out over the top edge of the alu ring, and continuing down its outer face for another 50mm or so, or as much as can be achieved without impeding the block-fixing-eyes cast into the lower edge of the ring. Prior to lifting the masts these rigid boots had to be ground off with careful use of an angle grinder, including taking off some of the material bonded to the mast to allow the deck ring to be lifted. It's a very neat solution to waterproofing the partners, and both masts gave not a hint of water ingress, either before or after the mast removal. The attached photo shows the foot of the mizzen mast with the original rigid boot.
Hope this helps.