3 lap ride.

Why not a solid steady ride slightly less effort than your last HIM?

Would you do this on a regular HIM bike?

I don't think the course setup should determine your race plan.
56 miles is 56 miles. point to point and multilap should have the same strategy only with multiple laps you get to see the same hills over and over

I did a tough (bike) 70.3 course, Saturday. I wouldn't suggest "hammering" anything, if you compromised your run, last time.

Do you have a bike computer? Power meter? I would aim for a pretty steady pace/effort for each lap, easing into it a bit at the start and backing off a bit in the last mile or two, doing a higher cadence in a lower gear to loosen up the legs a bit for the run. The latter really matters for me--pretty much every time I've cramped and struggled on the run (which is my strength), that's been a factor; and/or pushing too high a gear into the wind or uphill.

If it's a hilly or windy course, that's where a power meter can really come in handy, because it can be hard to tell from speed alone how much work you're doing--you can feel like you're going nowhere (and not be going very fast) but actually you might be destroying your legs for the run. And with tailwinds and downhill false flats, it can be tempting to just cruise along because speed looks good, but actually, you should be pushing more. If you overdid the bike on your last race, I'd aim for a somewhat lower speed/power/effort level this time. Personally, for me in a good HIM, the bike leg feels like I'm pushing it beyond my comfort level for a long ride, but I'm not in agony at any point or thinking I can't finish the ride.