That looks like it might be a great option for mostly paved riding and light gravel or dirt. Keep us posted if you end up order them
Load rating might be a concern since they're for older bikes.
Same or similar tread pattern as the IRC 3R, it might even be that tire model just as a Honda part number. With it being an OEM part for 1970s-1980s bikes, you would want to make sure it's not past its shelf life and has been stored well. New-old-stock tires are only good for show.
The Shinko SR241 is likely one of the softest tires available for this bike, I would expect any tire to outlast it in longevity. The SR241 is a great choice for off-road traction, just not pavement miles.
That's a great question because it varies by tire model and tread type. Trail or trials knobby tire dimensions are going to be a lot different than both street and dual sport type tires. If you're looking at a knobby tire in 2.50-17, it will likely be around 1/4" narrower and possibly taller in circumference compared to the stock tires.
For example the stock tire is IRC GP-5 is 80/90-17 on paper, where 80mm = ~3.15 inches, yet in the real world it's only a tiny bit wider than a 2.75-17 Shinko SR241 that is 2.75" on paper, due to the tread blocks protruding from the side of the tire. The SR241 2.75-17 tire is also taller (larger circumference, oversize) due to the tread blocks/knobs.
The OE tubes are a mix of butyl and natural rubber that hold air well but aren't especially puncture resistant. Some of the mention of punctures may be from mounting the tire by hand with spoons and puncturing the tube. I've pinched tubes mounting by hand, it's easy to do. The risk of this can be reduced by using more care and patience, using a tire machine, or using something like the
zip tie method to keep the tube from coming in contact with a tire spoon. If you want more puncture resistance you can switch to a natural rubber tube with the compromise that it is more porous and will let out air over time so you will need to check your tire pressure and reinflate them to spec more frequently. Natural rubber is also easier to patch IMO, but that's only relevant if you carry a patch kit and tire inflator.
I ran these tubes in a set of Shinko SR241 2.75-17s which are a very overkill solution and I had no flats for the life of the tires (replaced when rear tire was square and bald):
https://www.revzilla.com/motorcycle/double-tough-inner-tubes?sku_id=1132924
I am currently running these in a set of IRC TR-1 2.75-17s because they're inexpensive and accessible, also had them in the prior (one or two?) sets of tires without any flats:
https://www.revzilla.com/motorcycle/bike-master-performance-motorcycle-tube?sku_id=1087209
Something like a screw would puncture an aftermarket tire and tube the same as it would the OEM ones. IMO don't worry too much about a problem that you aren't currently facing, just have a plan for how you would deal with it. That might mean carrying a bottle of tire repair sealant, a tire inflator, tools, a spare tube, a patch kit, etc. or it might mean just having a cell phone on you and the number of a friend who would help you push the bike and load it into a truck to deal with later.