Simple Diluent For CBD Vape Liquid? DIY?

I have full spectrum, hemp derived, winterised CBD extract that I want to dilute. Its about 50% CBD, it doesn’t crystallize but it is a bit too thick for most vapes. Really though I want to dilute it to lower the strength a bit and to give me more flavor options using terps. I’m in the UK so I can’t get hold of much else.

My plan so far is to:
Find out which terpene(s) would be best for diluting high CBD extracts (Hopefully you guys might help with that!).
Start with 5% diluent and 5% terpenes for flavor and go from there.

So far I’ve read that common sesquiterpene like beta-caryophyllene, nerolidol etc might be simple cheap way to go. Also, bisabolol, phytol, D-Limonene and Farnesol are commonly used. Squalane is apparently not as good when used in high CBD situations? I understand some may effect the flavour and colour more than others which I’m ok with but the more neutral the better.

I know this is a tricky topic, but if anyone has any reasons as to why a certain terp might be safer to vape that another, I’d be interested to know.

Thanks in advance.
Kit