I’ve been running the large bore machine for the last 8 years or so – and feel your collective pain when it comes to tapering stock. OEM tailstock is adjustable, but as described earlier, it is a pain to set accurately for the taper and then return to straight work. Went the 2 tailstock route for a while, but ended up needing different tapers for different situations, so that wasn’t the most efficient. The taper bar approach Chris is working on will add a great deal of flexibility to this machine. But in the meantime...........
Then found an adjustable live center that has simplified things, at least for me. The vernier dial, in conjunction with an indicator, allow me to set what I need, without messing up the OEM tailstock alignment for straight work. Granted, more tools open the door to less accuracy, but this has worked for me. Found it on ebay (using the title in the attached pic). It is offered with a Morse Taper, but upon further inspection it was also available with a 12mm straight shank – less than $100 USD. Just checked and the 12mm option is out of stock, but might be worth keeping an eye on. Perhaps there are other vendors.
Good Luck
keninar