The BS34 carbs you were supplied with are better than the BS38's that came on the bike. Those are the carbs the Yamaha switched to in 1980 so they are perfectly suitable for the bike. You will need the corresponding BS34 intakes to bolt to the head though. With few exceptions aftermarket ignitions tend to very expensive and not as robust as the OEM systems. If It were my bike I would keep the points, others will vehemently tell you that you "the ignitions and charging system are the weak link on these bikes"
despite the fact that they have worked perfectly for 40-50 years. Points/condensers are cheap and robust. A very quick search of this forum will produce weekly posts all to the effect of "aftermarket ignition, bike wont run, please help!" many tend to be very long threads that result in the purchase of yet another aftermarket ignition because the first one didn't work. The ones that do work often exceed the initial cost of the bike.