Just enough money to raise 3 kids in a rich country without having to work (so he can focus on whatever project he wants) and no more. Then maximize fame.
Fame is slightly convertible into money with generally little liquidity, but is more valuable if money becomes useless in a TEOTWAWKI.
Of course, in the end, one just does whatever seems cool and useful, and the Gods decide what proportion of fame/money/power they will get. Due to Ciro's love of open source software however, a higher fame percentage seems more likely than money.
Searching just for just "Santilli" on Google does not give any Ciro Santilli hits. The name appears to be a minor variation of the much more common "Santini". Since the name is not that common, it is possible to go over all noteworthy hits. Some relevant ones are shown at: interesting members of the Santilli family.
Searching just for just "Ciro" on Google does not give any Ciro Santilli hits, mostly some smaller brands that could be beaten, this is Ciro's main initial fame metric goal. Reaching it would require doing things known much beyond the programming community however, as Ciro has done until of 2019. http://ciro.com is from an electromechanics consultancy as of 2019, so it's not bad, let them be.
The ultimate dream however would be to beat Cyrus the Great himself on Google searches ("Ciro" == "Cyrus" in Portuguese), maybe becoming "Cyrus the Greater"? That one will be a bit harder though. Maybe if Falung Gong becomes the dominant religion in 2000 years like Christianism did, catapulting the Judaism benefactor Cyrus into greater fame, then there is some hope for Ciro as well.