First of all - make sure those ancient Strombergs (97's? 81's?) are any good. They do wear out, leak air and/or gas and can be a general PITA to make work right at~75 years old. Once you are sure they are in good shape, with a good neoprene or other space age material instead of steel-on-steel inlet needle and seat, a neoprene accelerator pump instead of the leather originally used, the throttle shaft not leaking air, identical jets (you need a special wrench for them), you are ready. While that Uni-syn is a nice tool, it really isn't needed for a dual set up. Adjust the idle screws to seat, then back off 3/4 to 1 turn then start the engine. Use a vacuum gauge and work those idle screws to the best at idle setting - you are then done - go for a ride. Enjoy.
A couple of points - if you have an original distributor, that vacuum advance will not work correctly** - there is no mechanical advance. Next, those two Strombergs together might not be much if any bigger then that screwy looking original "back draft" carb used on Merc's, hence no real performance improvement. The Holley's used '49-'53 and a variation '55-'56 are a bit bigger, more readily available, cheaper and with parts easier to find.
BUT - it sure will look nicer