I have about 40 positions.  I think of my larger weighted shares like Apple, Google, Facebook, Adobe, Salesforce and ETFs almost like "safe, low risk positions".  They range from about 8% to 14% of my portfolio each.  I then limit my more risky shares to $1000 and buy up to 3% worth if they are higher conviction.  If they go up I trim to derisk by selling down.  I do wish I invested more in ETFs, thereby having less companies to track.  The biggest issue I have with having a large portfolio is following them all.  ETFs and my low risk positions pose me no issues at all and have generated surprisingly good growth with no end in sight.

I've gone 60% at cost into 1 position before and these days I'm much more concentrated than strawman allows me. This really depends on the opportunity and conviction. It might seem risky but it's a lot less risk than the founder takes on in creating the business. Often they will deploy 100% of their capital to get started and work for no wage. Also, I'm young with no dependents.

While I was newer to investing, I was never comfortable with more than a 5% position. I think this was a good approach and place to be while learning and making mistakes. Frankly, I didn't have a clue what I was doing. One of my investments at that time went to $zero as well...  (receivership!)

This is a really interesting question, I've been building my portfolio for roughly 13 years and currently have a bit under $800k invested, I start new positions in individual stocks pretty small now around 1 - 2% of the total portfolio value or 5 - 7% for ETF's. I think that's partly because I started mid 20's, am now late 30's and my risk profile has changed - I used to have more time, now I have less time left and more to lose. During the March 2020 melt down I mostly focused on EFT's like MOAT and NDQ - partially because I had trouble working out the individual stock risks given how quickly things were evolving and running home schooling took too much research time. Now I'm a nervous Nelly I have 2 position sizes that make me a bit uneasy so I have been lightening or considering it. Very interested to hear some people have only a handful of stocks or buy 10% positions, I have two 10 baggers (CDA and CTD) that now make up 20% and 15% of my PF and I'm constantly internally debating whether I keep letting them run vs keep trimming - have been having the debate since about 3x each so my inaction has been lucky thus far. I also sold RMD and CSL ten years ago so those massive screw ups helped me learn at least. 

I don't have much capital to allocate so I wait for a couple of pay cycles to build up my investable amount.

If I have a high conviction, but it's a small cap company, I will generally just buy the minimum number of parcels and then hold just so I have a position. And then top up if I see my thesis is fundamentally sound but it dips on market volatility etc.

If I have a high conviction, and it's a medium to large cap, I will try to buy a lot more parcels to maximise my brokerage. When I was trading with CommSec I generally either did $1000 or wait until I had saved up about $5000 to put down otherwise the $20 brokerage wasn't good. Having said that, I've now switched to Interactive Brokers, and their brokerage is lot cheaper so I can buy $2500 worth for example and not get slugged $20.

For ETFs, I just DCA into them but try to buy on market volatility dips even if it's a slight dip I will top up. With ETFs I probably pay more attention to the chart and buy on or below the 20 EMA if I can but it's not strict requirement. I only have 3 ETFs really, VAS, NDQ and ASIA... and recently I've just been topping up on ASIA due to the massive dips.

Hope that makes sense.