Oceaneer - I think I may know your boat. Anyhow, here is one vote from a Vancouver BC based Catalina 36 - proportionally heavier than you but still at just 36' so a bit less loaded up.
I carry two kites. The heavier one is a 0.8oz which I use over 12 knots true right up to 'I'm scared' conditions. It is certainly straining once the breeze ticks over 20 but that happens about once every 3 years here.
The lighter kite is a true 0.5oz with heavier panels coming out of the corners. I'm not sure if the heavier panels are just Airex 600 or if they are 0.75. This kite works great in our more typical 5-8 knots TWS and has that bit of extra safety factor when you overstand the mark and need to load it up to reach in.
A-kites do load the luff more than sym kites as you typically are carrying more apparent.
For your boat and what sounds like your uses, I would go no higher than 0.75 for the kite but would almost definitely go up a cloth weight for some or all of the luff. This could mean going to 1.5 or just a more expensive cloth in a similar weight. A really good sailmaker should help you with weights and layout. If you are in the PNW and in Canada you get to choose from North, Evolution, LeitchMcBride/Sobstad, or UK. There are a bunch of mail order houses in BC who are going to push you to 1.5oz simply because they have pre-existing designs that are all based on the heavier cloth and they are picking specs off a spreadsheet rather than doing actual design work.
Most 'cruising Asym' kites on other Catalina 36's seem to be 1.5oz mail order jobs. They start to actually work around 10 or 11 knots TWS, and most of these guys promptly take them down around 12 knots TWS because they are almost as fast wing and wing under whites and the wife is often getting tense right around then.