Time to replace the clutch! Which one should i get?

Hi all,
Have a 66 series IIa, 88. Clutch is slipping. RN has the proline clutch plate and pressure plate. There is also the LOF ROADspec clutch kit at Atlantic British. Any advice which one is better? Definitely don't want to do this again in couple of years time so need one lasting the longest. And how do I know if I have the 9 vs 9.5 inch plate? Do i have to take apart everything first to see or is there a way to tell by the year etc?
Pleas advice
thanks!

Your truck should take a 9.5". The roadspec clutch is supposed to be the business. Or the best "normal" parts are probably Bearmach.

Thanks!