185,sportsman stol,20 flap,trim just a touch nose up,set throttle so that aircraft stayed around 60 knots
'Sounds right to me....
Elevation and temperature can really make the takeoff run a lot longer.
There were some high and hot lakes in South Africa.
Yes, the affect of elevation and temperature on performance is well known. When I landed the Twin Otter on the runway in Harare (formerly Salisbury), the only advice from my mentoring pilot was: "Land long." The runway was around 15,000 feet long. I was later told that this length was needed for the BOAC Comets which flew that route decades earlier, and suffered performance loss in the climate.
Float flying demands that the pilot be either a very good or very conservative decision maker. Commercial float operations seem to have these locale decisions mostly pre made for their newer pilots, which is great. It's private operations which can be troublesome, as a pilot just decides to land in a pretty lake, without really having all the factors affecting departure worked out.
One of my most pleasant and valuable recollections of a visit to TC decades ago, was simply overhearing a conversation between Inspector J.P. Sr. and a pilot flying a Maule floatplane somewhere. JP asked a few questions of the pilot, and apparently determined that he was low experience. What followed was about 15 minutes of pure gold "save your butt" type advice. That pilot (and I) got way more than our tax dollar's worth that day.
The most memorable element of what JP taught the pilot, and me, by eavesdropping, was that as you circle your intended lake, take the time at altitude to sketch the lake, north, the wind as you perceive it, any hazards or obstructions, your intended landing (and departing, if different) path(s), and where you intend to beach or dock the plane. Once you're on the water, it's going to loo very different, and you may wish that you have a bird's eye view to help you choose the best path out - may as well get it while you can! This sketch will force you to consider the hazards and obstructions you can see, relative to your water run paths, which lessens the risk that you blunder into something bad. And int he very worst case, something does go wrong, you have a paper record for the insurer, that you really did think about what you were doing carefully.
It is very true, that once on he water of small lake, things look different. Without reverse, you may be reluctant to taxi into a confined area, or go around a tight corner, but that might actually be where you came from, and where you need to be for a safe takeoff. Your sketched map will remind you that yes, that it is the way, or no, don't go there, you saw a shallow rock from the air.
Generally, when float flying, you do not have the advantage of established airport infrastructure - airport diagram, wind sock, assured operating areas on the surface. You must rise to the occasion of making good decisions based only on what you see and know, and your skills. This is certainly not the time for optimism, and boldness (you already did that, you're there!). It's the time for reasoned, and very conservative decision making.