I just lowered the mast on the Catalina 250 two days ago. This was my first time and I made my own gin pole. The Catalina 250 is designed to be trailerable, which makes stepping the mast much easier. For instance, both the upper and lower shrouds are behind the mast (thanks to the swept-back spreaders), so they loosen as you lower the mast. There are no forward lower shrouds to remove - just the forestay, since the mast pivots toward the cockpit.
While your mast may step differently, perhaps you can get some ideas from my setup.
Here is my gin pole, which worked great:
That is a 20 year old spare tire bracket used to attach the pole to the mast. A new one that I had bought was heavier gauge rod, which left insufficient room for the nuts on either side of the 2x4.
The only thing I might change with the gin pole is to put a different winch on. It was pulling pretty hard against the short handle, and though I never lost control, had I let go I would have never regained control with the ratchet disabled. It would be nice to find one with adjustable friction brake. Does such a winch exist?
Here are pics of the pole rigged up. The red ratchet straps kept both the mast and pole in column by connecting to bails on the stanchions, which on the C250 are conveniently aligned with the stepping bolt. (Catalina sells "baby stays" for the mast, but they were pricey and would require me to wait longer than I was willing.) Since the straps do not have pelican clips, I used duct tape across the opening to ensure the ones to the mast did not fall out. You'll see two lines coming off the top of the pole. I used both the jib halyard to the top of the mast AND made a harness to run a second line to just beneath the spreaders. I wanted redundancy for this critical function. The red bucket in the pic is there to put the furler into so it does not scratch up the figerglass:
My biggest delay was caused by difficulty disconnecting the forestay. The C250 has a split backstay, so releasing the one on the port side (which has a shackle for this purpose) would loosen the backstay nicely. But I could not get the port backstay shackle to release because it was so taut. I had to turn to backstay turnbuckle (inconveniently located about 7 feet above the cockpit) 20 turns and have a friend pull down as hard as he could on the backstay to get the port shackle to release. After that I was able to easily remove the forestay. The owners manual gives no hint that releasing the forestay is so complicated.
My crutch for supporting the mast did not work perfectly, largely because I could not find a good place to secure it in lieu of extra gudgeons on the transom. (Rudder does not remove easily because I have wheel steering.) I used a bimini swivel with removable clevis pin attached to a metal loop welded into the rear pulpit to bear the brunt of the weight, and a broom clamp below it to keep the pole vertical:
The moment arm was awfully long, so I relocated the parts to shorten the crutch. It was stable enough to support the mast once it dropped, but when we removed the step bolt to walk the mast forward, the forward force on the crutch was too much (even with the roller) and the broom clamp released. I ended up reinforcing it by lashing to the pulpit, but I'm uncomfortable with relying on the pulpit since it's just attached to the fuel locker with nuts and small washers. I'm afraid a good wind storm against a tarp could put too much pressure on the crutch and damage the pulpit or fuel locker. So after I took these pictures I lashed an 8' 2x4 across the perch seat pulpits and set the mast on it for the time being. I need to find a better alternative for under the tarp, so I'm thinking I'll put a sawhorse across the cockpit lockers.