Lenny,
Allistair’s recipe is designed to get you the best possible mono recording with the minimum of noise.
Koz’ posting is basically about the same stuff - he is telling you that you won’t get a true balanced mono recording due to physical differences in the track on the record and the response of the cartidge. Allistair’s recipe corrects for that.
If you find Allistair’s recipe too difficult to do and if you feel like spending a few dollars then you should consider using Brian Davies’ excellent ClickRepair software (a steal at $40 IMHO). In addition to being a truly magical repairer of clicks and pops on your recording - it also has a stereo to mono conversion function (operated simply by making a little tick in the right tick-box). This will then do basically what Allistair recommends, - but does it all for you with no other messing. See this thread of mine on ClickRepair: https://forum.audacityteam.org/t/click-pop-removal-clickrepair-software/1933/1
I used ClickRepair’s Stereo to mono function a while back to correct a Carole King record (It might as well rain until September) I had which had reprocessed by the engineers on re-issue to false “stereo” on an LP. My original mono vinyl 45 got trashed badly on my jukebox 
. Taking it back to mono this way improved it greatly.
WC
Update: and if I remember correctly Lenny, you are working with 78s. In which case you should also take a look at Brian Davies’ DeNoise software (also $40) and his Equalizer software (free). All of Brians tools are available on a 21-day free trial so you can test out whether they work for you before committing to purchase. WC