You would not need to get rid of the roller furling gear, just not use it. To set up slab reefing, you will need to add some blocks. Some of this depends on how you use the boat and how badly you want to modernize the boat.
The simpliest solution is to add a sheave for the clew line for each reef at the aft end of the boom and a cam cleat near the mast so that you can pull in the reef. On a 30 footer you can simply use a short piece of light line that passes under the goosneck to tie down the tack. That line can actually be permanently attached to the reef tack cringles all ready to go. But that does not get things back to the cockpit.
But since you (Like myself) single-hand a lot, I would agree that it would be a lot safer to be able to reef from the cockpit on a boat this size. That would require quite a bit more gear. To do everything from the cockpit, in its simplest description, it would mean running the main halyard aft to a stopper and winch at the aft end of the cabin and then rigging a two line reefing system with lines run aft for each reef clew and tack line, as well as the outhaul (although you could simply add a cam cleat near the mast on the side of the boom for the outhaul).
To go run the reefs from the cockpit, essentially you would need to end up with three sheaves (either a triple block or a cheek block each side plus a block on top center) at the aft end of the boom (Outhaul, Clew line Reef 1, and Clew line Reef 2).
You will then need to add three sheaves near the gooseneck that turn the lines down toward the deck. Then you will need six sheaves at the deck (main halyard, outhaul, first reef clew and tack lines, second reef clew and tack lines) which aim the lines aft. (You may want to add one more sheave at the deck for the jib halyard and another for the boom vang. I would.) Depending on your deck layout you may need (a) deck organizer(s) (probably 8 sheaves if you also run the jib halyard and vang back to the cockpit).
Lastly you will need a mix of stoppers and cam cleats, one for each line in order to make this all quick to use.
On a 30 footer, it may be cheaper to simply make a new aluminum boom using stock end fittings, which typically include the three aft sheaves and the three down sheaves and which also allows all of the control lines to be run internally.
The nice thing is that it gets a bunch of stuff off the mast so the jib sheets are less likely to hang up (A really bad thing in heavy air single-handing). The bad news is a lot of line back in the cockpit and new gear to buy and install. (I actually have seven stoppers lead to a winch on each side of my cabin with 14 lines run aft but I also have my symetrical spinnaker gear and a space for my P&S preventers run aft.)
There should not be a problem adding a jib roller furler on a boat this size although it really isn't necessary. A reefable jib with hanks and a downhaul may be suitable for short-handing a boat like this. Double-headstays are unecessary and frankly a real nuisance on a boat this size.