First off, welcome to the forums.
Second, I wouldn't get too caught up in the marketing-speak regarding the longevity of the Panasonic discs. Their discs, regardless of variety, seem to be the best available, or at least, some of the best we can currently buy. I've not heard of or seen any Panasonic discs that used LTH technology, so I think you're safe in that regard.
If you want a less expensive alternative, you might look at the FTI Falcon discs. They were not included in the one durability test that everyone seems to refer to when talking about the longevity of Panasonic media, but the FTI discs burn well and I've seen no deterioration in playback from them over the last 5yrs. This may not be enough evidence for you however.
And just to be clear, I bought my Falcon discs at Media Mega Mall under the SmartBlu brand. They are considerably cheaper per disc, but that site charges a lot for shipping and have a surcharge on small orders. You can see them here: http://www.mediamegamall.com/smartblu-premium-bluray-disc-25gb-silver-lacquer-print-25pk-sbr4ssh25-p-27685.html