cheese is by no means a "pure strain". it's really just a pheno of skunk #1 as is lemon skunk, & roadkill.
if i could preserve ANY IBL, it would have to be columbian gold. it may not be the absolute trippiest ever, but it's what i started out smoking and NOTHING i've smoked since can match it's fun trippy buzz and the light floaty feelings it gave. i'd preserve that one just for nostalgia, but if panama red really is better, maybe i'd go with that instead.
for preservation sake, i'd want to mix it up with IBLs from different areas so future generations could revive fading genes by crossing with stuff from other continents. it always whizzes me off when breeders take something like gold & then permanently pollute it with indica instead of crossing it with a different strain with more of a similar buzz like thai or even haze. once you pollute those genes, you can never get them back.
after gold, i'd save highland thai. that's a trippy strain and when you experience the real tutti fruity flavor, it just makes it extra special. i wish i'd been able to smoke some bud of that. really, sativa seeds is already on that with their full moon, but it wasn't on the market just a few years ago when watered down with indica juicy fruit or various DJ shorts strains were as close as you could get. after sampling just some leaf & TINY bud starts of that, i'd hate to see it go extinct for sure.
then, i'd get some cambodian or vietnamese blackseed. those might be THE champions for trippiest strains ever. asian strains in general are pretty good for psychoactivity
4th, i'd want to get some afropips lemony malawi gold. it's trippy and probably the best strain from africa.
finally, i'd probably want to preserve burmese which is also lemony and close to asia, but it's one of the most compact trippy IBLs out there. it would make a great breeder for indoor strains. i always wanted to try and shrink malawi gold down with C99 & burmese to get a nice lemony trippy strain, or cross it with the best cali-o that could be found for a trippy orange strain.
then again, spicy IBLs are awesome too. i had some mexican brick that was exceptional and that had a very similar taste to ORIGINAL kali mist. both had really hot flavors not unlike crushed red pepper. the most recent report i got on kali mist 2.0 says that now it's just spicy with hints of fruit, but the buzz sounds undamaged by the update. yeah, i think i'd go with a peppery pure "western winds" cambodian for a clearheaded energetic buzz with really nice euphoria to contrast the milder flavored & fruity trippy strains.
if i knew more about the strain, i might be inclined to say kerala as it's an indian strain.
i'd like to see more people trying to grow and preserve what's left of the IBLs. indicas are everywhere & don't need to be preserved and have a full range of hybrids that have all kinds of flavors. those take care of themselves. you can get probably dozens of different IBL lines of afghani still and it's pretty much in everything these days anyhow.