French to English Marketing sports sponsorship - press pack

Finishing off a press pack and need some help with titles. It’s a sports sponsorship and there are varying levels of sponsorship/partnership) involvement. What I am looking for is a way to differentiate these levels in the way the French has. My problem is with the second one, “les parains”, who lie somewhere between the main sponsor and the strategic ones.

An extract from the Contents page with my notes explaining the type of involvement :

III.1 - XXX : le partenaire titre
(the main sponsor after whom the boat is named. These guys have put up hard cash)

III.2 - Les parrain
(companies who have provided funds to assist in putting the project together)

III.3 - Les partenaires stratégiques
(corporate partners providing products and services)

III.4 - Les partenaires officiels
(corporate partners providing free goodies)

III.5 - Les partenaires
(partners providing goodies plus special offers and advantages etc for the team)