Hi Nanook of the North! 375 Gallons, that can be something really special. I'd like to offer my opinion on some things you ought to think about though.
First of all the worries about wet/dry filters and CO2 is largely based on myths. There have been experiments done via side by side comparison of a trickle syetem and a non-trickle system (bare tanks, no fish, no plants). The result was that there was not much difference in CO2 loss between both systems. If you are using a pressurized system (and I assume you would with a tank that size) all you have to do is open the valve more to get the recommended levels. The effectiveness of your CO2 will largely depend on your injection method rather than what type of filter you have.
Were you also aware that, assuming proper nutrint levels are maintained, adding CO2 can boost plant growth up to 3 to 6 times even on a low light tank? The reason I point this out is that you seem reluctant to engage in any sort of pruning or maintenance. If you really dont want to prune or change water I would suggest you keep low light, slow growing plants. You could fill the tank with various species of Swords, Anubias and Cryptocorynes.
You also asked about water change regimen. Plants and fish suffer due to water pollution so this is what we're trying to avoid in a closed system. A large low stocked tank has much more room for error than say a 10 gallon simpy as a reult of the large volume but at some point poor maintenance habits, no matter what size tank will cause problems and will be reflected in either disease or algae. A "typical" regimen is 25% of the water volume per week. In a 375 Gallon, with gravel, decoration etc. you may have only 4/5ths the tank capacity in actual water volume so you may have only 300 gallons (by the ay it's always a good idea to count you volume when you finally are filling the tank so that you will always know. This helps to dose medication and fertilizers later on). This would "typically" mean 75 gallons a week. It's your tank though so do what you want. If you prefer to do a biweekly change then start with that and see how your tank responds. If you are seeing problems either reduce the interval or increase the volume or do both.
Let me just say one thing though - your two statements;
"...a large community tank with a striking aquascape of plants, rock and wood landscaping..."
"...don't want to spend my time changing water weekly and pruning plants. I think I would get rather tired of that routine..."
These are almost incompatible statements, at least in the beginning. An aquascape is a garden just like the one outside. Do you really think nice gardens have some kind of remote control where the owner just presses the button and viola, striking beauty? I don't think so. You have to be involved with you tank, especially one that size, otherwise you're likely to have a 375 gallon algae farm.
This is how I do my large water volume changes: I have my 150 gallon tank located near a window leading to the garden. I collect my water early in the week and store it in a couple of 55 gallon plastic drums in the basement. with a long hose I siphon the water out of the tank and use the suction to vacuum the tank scraping any detrius or algae from wood, glass etc. the output of this vacuum is collected in other plastic drums outside or, in the summer directly to the garden. I have a large pond pump that I place in the basement collection drums and long tubes that lead to the tank upstairs. Start the pump and wait. The more powerful the pump the faster filling goes. It's really quite easy and if you do it regularly you become quite efficient at it. It's much more like a fire brigade. With large volumes DO NOT change water with buckets. Perhaps it's the thought of the bucket brigade that is turning you off to water changes?
In any case I would venture to guess that the beautiful tanks you see on this site and others are seldom if ever achieved by putting them on cruise control so you may want to consider starting with lower light, perhaps 2 watts per gallon and low light plants and see how it goes. Hope this helps!