I like the NGK plugs with HEI. In my VL Brock stroker I run BP6FS (NGK # 3512) - but it's running straight LPG and higher compression.
They're 1 heat range colder than the standard plug, and work well with LPG and compression

Iridium is just an exotic metal used on the tips that resists erosion for far longer than standard plugs. Same way platinum was used for electrodes to give a long life - but iridium is even better. Most OEMs use them as standard fitment now. They can go at least 120,000km or more. I've only changed the plugs once in my 2011 FG LPi (liquid injected gas), and it's got 280,000km on it now. I changed the originals at 150k, and I'm planning on doing another set at 300k.

In a weekender, you'll likely never need to change standard plugs, let alone long-life ones, so the extra cost of iridium may come into consideration - BUT - and this is only my "seat of the pants" feel - the tiny electrode size on the iridium plugs seems to allow more flame propagation when the going gets tough (cold starts, flooded engine etc) so to me they're worth the $100 or so more than regular plugs for a set. When I do the plugs in the Brock next, I'll be fitting them.

The cost has come down over the years, as manufacturers have been making the iridium tip thinner & thinner to save money, so the cost gap isn't as bad as it once was.

Just one thing to be very careful of - use gapping pliers, and don't put the feeler gauges in and hammer the ground electrode against them - it's easy to wreck the thin iridium tip.

You need a minimum of platinum for HEI. My experience with iridium has been less successful but it was with two stroke dirt bikes. They were absolutely useless. However that’s possibly not a great comparison.