I think you're overestimating the difficulty of just disassembling the entire winch.... if you're careful and methodical,
it's quite simple...
Anyhow, you'll find that you must remove the drum to get at the top bearing.. it's a cylindrical cage with roller bearings... much easier to lift off the drum.... the bearing may stay on the spindle, or stick inside the drum cause the grease is probably old and dirty. You must be careful with the pawls and springs as you lift it off.. The second bearing set should be removed, cleaned and lubricated also.....
Here's a step by step instructional piece:
Winch service
Sounds like you have never properly service your winches... this is a good time to learn.. after the first, you'll want to inspect and service the rest of your valuable winches..... so... go ahead and invest in a tube of Lewmar winch gear grease and a small bottle of oil for the pawls and pawl springs. They sell it as a kit, and pictured instructions are included. All winches are basically the same once the top cover is removed,. Oh, and btw, you can purchase spare pawls and pawl springs made by Lewmar that will fit your Barient/Barlow winches... I know West Marine sells them.... maybe here also, but the pawls are basically a universal fit, the springs are either both legs straight, or one leg bent... either will work, but I think the Barient/Barlow winch uses the bent leg config.
So.... go for it...you'll feel quite good about yourself when you complete the job and be highly confident it tackling the others. You may find it much easier and more convenient to actually removethe winch from its mounting entirely and do the rebuild at home or in the cabin. Then you can rebed properly also.
Have fun.