Hi Jimmie . . . sounds like you're well on your way to a great cruiser. I agree with your assessment of the two options. One is a dual action fuel pump that will provide a constant vacuum source. The other is a kit to eliminate the vacuum assist. Chevs of the Forties has both:
Fuel+Vacuum Pump
Vacuum Assist Conversion

If your vacuum assisted shifter is working well the vacuum pump is likely the path of least resistance (it maintains originality and will help the Wipers too if you plumb them in). But they are ugly compared to the glass sediment bowl device usually found in this spot. I don't think the vacuum canister would be necessary with the dual action pump.

I don't have any experience with the mechanical conversion kit.

In '49 Chevy went back to an all mechanical linkage. It works well so long as it is kept lubricated. If allowed to wear the shifting rods sag and then bind. The geometry is maintained only by flat washers and cotter pins . . . hardly a precision piece of engineering . . . but effective if lubed to prevent wear.

regards,
stock49