The rule about chain length depends on whether or not you're using a "modern type" of rear derailer (with a sprung upper pivot) or your older Suntour (without a sprung upper pivot).

With the Suntour derailer, the chain length "excess" when on the large/large sprockets should be checked with the chain installed in the derailer, elsewise you risk ending up with a too-short chain, and possibly a no-shift condition when trying to shift off of the largest rear cog.
As Shimagnolo alluded to, you'll have to consider what chain length exceeds the limit of looseness when using the smaller sprockets, although riders like myself never use the smallest sprockets together and thus have less to worry about in terms of a too-long chain.

Keep in mind that a quarter inch of axle movement in the slots will change the chain length requirement by a half inch.

Did someone suggest that Shimano's special (one-time, non-removeable) chain connector pins were obsolete?
Even the latest 11-speed road gruppos use these pins, and with no hint of this changing.
Shimano's pins are very good, but require some commitment as to the installed chain length.
A specially-pinned link can be removed from a chain, but only after grinding the heads fully off of the pins on one side of the link, and then popping the grinder-thinned plate off. A KMC link can then be used if one wants to restore the original chain length, but chains normally don't ever need to be removed until replacement time, or for gross changes in gearing.