Thanks... this explains a lot... I did it with a 16 Watt... I will order a larger one now.
16W may not melt thru all solder in the via/hole.
Quite acceptable for your method but hard to get it just so.
You must have the knack for it and more patience than me.
If you did it with 16, 40 will be enough for you forever, exception big power circuits.
Heavy tips help lots too if ya git er done quick, some spare heat!
(PSU, thumper amps, soldering AC wiring, etc.)
If it works it works.
A bit of time/frustration vs additional tool money, depends on budget/frequency of use.
YMMV