The problems with the "What about multiple attackers?" argument are the following:

For a normal boring John Smith citizen out in public in the US, without any threat enhancers (NOT off-duty LE with an obligation to "get involved", NOT owner/staff of a high risk business, NOT known to be carrying large sums of cash, NOT having other reasons to be specifically targeted, NOT living in the Favela), how often do they experience multiple threat attackers?

If such a citizen is accosted, how often do the perpetrators continue to press the attack once it is determined that the "victim" is armed, willing to shoot, or actually shooting back? From everything I have seen, the "scatter like roaches" factor is 99%+.

Until armed citizens are dying in the streets from a lack of capacity or lack of speedy reloads, the debate is rather moot. Given the large number of DGU events per year, these issues should statically manifest themselves if it truly was a problem.

Caveats:

Everybody should carry what they want, just don't think your EDC of a high-capacity polystriker with two extra extended mags makes you "better equipped" or "more serious" about defensive carry.

Nothing here should be interpreted as support for any legal restrictions on what can be possessed or carried for armed defense.

"What about Dicken in the Mall?" Yes- Mr. Dicken fired 10 rounds and hit the perp with 8 at extended distance with a G19 using ball ammo. Given his demonstrated skill level, I suspect a similar positive outcome if he would have been armed with a 3" Model 10 and 135 gr Gold Dots. His experience is more a lesson on the benefits of tactical marksmanship rather than capacity.

My personal typical EDC platforms vary from 5 to 8+1 capacity, are carried with a reload, and are usually complemented with a micro-BUG. In high NPE scenarios, the BUG may be the only thing carried.

With regards to the 642, my only preference would be for the 442 and it's easier to conceal qualities in our dry climate. Somebody in a humid area may differ