Don’t automatically pidgeon-hole yourself into a certain % of FTP based on broad guidelines. They’re fine as a starting point but ultimately are just averages. My ability to hold higher is partially training but a big part genetics. I actually have trouble pushing myself over threshold on the bike for anything more than a couple minutes, especially in TT position. I’m all slow twitch muscle and if I am riding/running below threshold, I can hold that effort for a long time.
You still have close to 2 months until your race, use that time to experiment with how you feel coming off the bike. White seems like a good starting point, but work yourself up to the harder efforts. What you may find is that your legs don’t feel amazing getting off the bike but you’re still able to hold a similar run pace. It’s not about how good you feel, but about how fast you go.
I would also recommend adding just short 10-15 min brick run to harder workouts above your target race effort- for 70.3’s I really love 90 min efforts with sustained intervals (15 up to 40’) at 95-99% of FTP (though I run off at a high Z2/low tempo pace just to assess how the legs feel not build fitness). They’re not in the TR training plans but they’re so beneficial physically and mentally prepping for race day. They also help build the strength and confidence to allow you to push more power into rolling hills and not be as constrained to an exact power number.