Please Suggest An Electronic Crossover

FM Accoustic.

Hello Mitch4T!  If you want it with fixed frequencies, use one of the units from miniDSP.  If you want to play around with the crossover points get a DBX unit (like the 223 - different kinds of connectors on different units) will let you have fun trying different crossover points. I have (and am using) 4 miniDSP and 3 DBXers. Great stuff!
Enjoy, Boomer Bill

+1 to eric_squires.  Bloody hell man!, 
Unless your vintage x-covers have electrolytic caps don't f* with them! Just pass enough juice to reform those old Mylars or what have you.  Replacement of resistors if they have gone out of spec could clean thing up a bit, but an attempt to re-engineer those x-covers will likely not end well. I've owned RS-1.5 and sadly parted ways, but still have some of my best audio memories those paired with an early ps audio preamp and a highly modified dh-220  built by an EE who worked for the sound lab in Groton CT. .

What could happen ....

I have used the Parts Express DSP-408 with good results. Offers a big slice of what mini-DSP does for next to no money.  Experiment with that and see if you think you’re making progress. You’d have to break out the woofer input to direct couple it. I agree that leaving the rest of the speaker xover for now is a good phase 1 plan. I have also used HHHF as a resource and Tony is great to deal with. Have fun!