Compatibility: clutch PK50 XL for vespa special

Dear SIP community,

I started driving a Vespa at the age of 14, going from a PX50 XL, to a 125 Primavera (got stolen :-(), ending with a Vespa Special...so, all the way through with Vespa smallframe. At the age of 28 I moved out of my country for work, leaving my much beloved Vespa in a corner of my father's garden. Now, 10 years later, I have finally decided to restore it fully: frame is in the workshop for sandblasting & painting and the engine is in my garage, waiting for the parts I am about to order for final re-assembly. From the outside it will look like the orignal but "under the bonnet" I want something more spicy than the original 1.5 CV engine.

I am thinking of the following engine, the target being a reliable, comfortable to drive and yet quick one: 130 Polini Racing + 51mm Crankshaft racing mazzucchelli + 27/69 gear-box + Auxiliary shaft 21-18-14-10 DRT + carburettor 19.19 SHB with polini filter + Banana exhaust + 1.6Kg Vespa Special flywheel, stator with DRT coil and condensator.

In order to increase the comfort and the precision of the drive, I would like to upgrade the standard 1-spring clutch with the softer & more precise 6-springs-clutch of the Pk50 XL. I'd order the sport version, with 4 disks&reinforced springs + the specific thrust plate + the DRT 1mm spacer for the clutch cover  but here is the question:

does the PK50 XL clutch fit with a gear-box like the Olympia or Surflex, which have basket with springs? Would the Pk50 XL clutch basket (wider, 74mm instead of the 65mm standard) touch the cover of the gear-box springs?

I know there are multi-spring version like Falc or DRT but they come with a price that I may spare: after all, the engine is not heavily tuned. It should be well below the 15HP and if the PK50 XL clutch fits with the mentioned gear-box, I think that would be all I need for my engine (or not?) 

Thanks to all for the support!

Raffaele