Thanks @Franco and @landrover. Most helpful.
@pastyj-2-2 because my primary use now days is bikepacking rather than bushwalking (hiking) packability comes in ahead of weight savings.
When I brought the Duplex I didn’t consider as carefully as I should the bulkiness of the tent when packed or more specifically how cuben fibre does not pack down as well as say silnylon nor how I could carry it given the very limited carrying capacity of a minimalist bikepacking setup (e.g., no panniers used where possible and when used, only used to carry a lot of water. For example on my next two week bikepacking trip I have to carry up to 15 litres at a time at various stages of the ride).
The packed size of the Blowfin from what I can work out will work better for me and given I am using a bike, the 300 odd grams of extra weight is something I can live with. I maybe also be able to downsize the Sea to Summit Big River dry bag I need to use (it has loops so I can better secure it [1]) on my handlebar harness and shave a bit of the extra weight.
To be honest if hiking was still a big part of my outdoor mix I would keep the Duplex and either just live with the difficulty of it on the bike or have a Blowfin as a second shelter. It is a good piece of kit and the weight saving is nice. Also if walking I could leave the carbon fibre poles behind save even more weight.
[1] It is damn amazing how much a dry bag can move and drop off the bike (so different from being in a backpack) … I had to do an extra two hours of riding on my last bikepacking trip as I lost my, what I thought was secure, food bag off the fork cage. Found it eventually but just made a long day even longer. New bag in use now with loops to make it sure it stays put.
Hope that helps.