Breaking/Joining Shimano Chain (SRAM Powerlink)

This isn't a fixed-gear related question but I thought I'd ask anyway as there are plenty of roadies on here.

I have a full Shimano 105 drivetrain on my geared bike and I cleaned it all a last week. I broke the chain at the one link which had a solid pin thinking this was some kind of joining pin (the rest were hollow and I thought this looked like my best bet). I then re-connected the chain using that same pin.

I thought nothing of it at the time but I was cleaning my brother's bike for him yesterday and his chain didn't have any non-hollow pins to drive through. After doing some research I've found out about the Shimano joining pins with guides etc. and so I tried my best to clean his chain on the bike.

I'm now worried that I've made a booboo with my chain. Does anyone have any advice on what I should do about it? Is this solid pin safe to drive in and out? I'm also considering getting a SRAM Powerlink to make chain cleaning easier (and on my brother's bike because he's inept at any form of maintenance).

You're supposed to use a new pin to join Shimano chains and snap the excess off when it's in properly. But, since I possess great skill and awesome power and am generally fantastic.. I've oftened reused Shimano pins. If you don't push them all the way out, you can break the chain and then push them back through. I've never had a problem doing this but my lawyers tell me that "your mileage may vary - try at your own risk".

I'm just going to Powerlink it. It'll remove the link I pushed back in.