SCP NPM March 2023 | Suggestions sought

Hi Everyone, 

I intend to take the SCP NPM exam by the end of this month. Haven't scheduled the exam yet, plan on doing so in the next few days.
Kindly share your inputs on the following concerns of mine:

1. I am eligible for any voucher? I don't belong to any partner organizations at the moment.

2. I read somewhere that by booking a single exam by paying 236 USD(including VAT), one is eligible for a retake within a year if one doesn't score the passing mark during the first attempt. Is my understanding correct? Is one eligible for taking two attempts for a single exam via a single payment?

3. Is the study material available in the SolarWinds customer portal enough for the prep? 

Awaiting your valuable response on this. Thanking in advance!