I've not got any experience of an A65 with straight mags as ours had an impulse mag when I joined the group three years ago. Starting was always easy hot or cold unless you accidently primed the engine when it was hot. The cure for this, and it might be worth you trying, was to slowly open the throttle fully (slowly to avoid the acceleration pump priming the engine) and then to wind the prop backwards through a number of blades. This sucks air in through the exhaust pipes to weaken the cylinder mixture.
At the last mags change (about two years ago) we changed from Bendix mags with a single impulse mag to Slix mags and both of these have impulse couplings. Starting is just as good as before. Hot or cold the engine normally starts on the first blade after the mags are switched on. When the engine is hot, eg after refueling, we don't even pull through a couple of blades - just mags on, and it will start on the first blade. The only time we have any difficulty is when its neither hot nor cold, say 30 mins after a flight, and its not clear whether to prime or not. We always try without priming first because its easier to add fuel to a weak mixture than remove it if you've overprimed.
Wonder if you ever get a kickback without an impulse mag? In 3 years and 250 hours I've never seen a kickback with our A65.
We bought the Slix mags because they did an offer and took the old bendix ones in part-exchange. Memory says we paid about £800 for the pair.
We had the engine zero-timed this summer (after 2600hours) and that cost ten times as much !