Sounds like you have a similar background to me but only 30 years in dinghies for me.
On Sundance I rigged a Selden telescopic pole on a sliding mast track so that it can be stored vertically which also makes the dip pole gybing easier as you can just yank the pole up the mast and the outboard end dips enough to clear the forestay. From memory the J dimension is around 4.0m so you need to go for the larger telescopic pole rather than the medium which puts the best part of £100 on the cost.
Starting with the spinnaker any sail loft should have the correct sail dimensions. I bought a Tri radial from Kemps as they charged the same for a full tri radial as for a standard spinnaker. Tri radials should be stronger and offer optimum shape for all points of sailing. The sail cloth was Bainbridge 0.75oz coated ripstop nylon which to date has survived well with no tears. The other thing I bought was a snuffer which is a must in much over 12 knots if you are short handed. I paid just of £1000 for the kite in January 07.
Rigging the halyard and pole uphaul is probably best left to a rigger as it is quite easy to get the halyard twisted around another halyard when threading (don’t ask how I know that) but make sure that the halyard still has plenty of length on it to let the spinnaker head fly off if you get caught out or broach. My halyard is 3 times the distance from the mast step to the sheave block plus the distance back to the coach roof clutch so I can probably let the spinnaker head fly off by 9 meters or so. Sorry I don’t remember the length.
If a rigger fits the halyard and pole uphaul make sure you include for additional blocks at the mast step, along with possibly extra clutches for the halyard and pole uphaul which you should lead back to the cockpit. You may also need to fit extra deck organisers further forward. I did and Rutgerson do one that will bolt on top of the existing ones fitted as standard. I have also ended up with 7 clutches on either side of the coach roof rather than the 4 fitted as standard that take the kite halyard, pole uphaul, 3rd reef and cunningham plus all the standard bits.
The running rigging you can fit yourself is the pole downhaul, sheets and guys plus associated blocks and clutches.
For the pole downhaul you need to fit a fold flat pad eye to the flat spot just behind the anchor locker. This is reinforced with an 8/10mm aluminium plate which can be drilled and tapped to take machine screws so no need for backing plates and nuts etc.
To this pad eye fit a turning block with a becket. Attach one end of the downhaul to the becket then take the downhaul up to the pole, through another block and back to the block on the pad eye so that you have a 2:1 purchase. The downhaul is then fed aft via stanchion blocks to a Rutgerson rope clutch on the outside of the cockpit coaming i.e the same type of clutch as the genoa furling line goes to but on the opposite side of the boat.
For the sheets and guys I have 2 full sets including the lazy sheets and guys i.e. 2 sheets and 2 guys per set, one set at 8mm and one at 10mm.
all at 20m long. I did not bother with barbour haulers on the guys as I thought that was a bit over the top for mainly cruising so I ran the guy straight through a block, again fitted to a folding pad eye on the flat spot close to the midship cleat which works well.
For the sheets I use a Spinlock 3 stage jammer which can be fitted to either the aft cleat or a pad eye via a webbing strop. These can be easily locked off so you don’t need to take the sheet to a winch to lock it off.
Probably sounds a bit complicated written down like this so I will try and remember to take some photos when down at the boat this weekend and post them for you to see.
Apologies for any spelling mistakes aswell. It’s been a long day at work.