Siegfried Jackstien - Thanks for the recommendation, I will research these.
John Gord - Re maintaining a consistent length between O, S, L - the three now provided with the nanoVNA are just RPSMA caps... therefore they should meet this criteria?
Thanks for the details on the article, Should be able to find it.
Donald S Brant Jr - Thanks for the recommendation, I'll research LibreVNA
Also, you're right re making your own...a matter of confidence vs doubt... I guess buying multiple kits then testing them all to see the alignment may help put faith in the chosen kit?