Who were the conservative candidates who didn't get Weld's support?
You name 'em. He sandbagged Romney in '94 because he wanted NO other Republicans who might actually grab some of the spotlight from him. He did zilch for the grassroots to grow the party beyond the Beacon Hill country-club clique, he badmouthed and excluded Conservatives (I don't mean candidates, but even just people wanting to participate). The only "Republican" he helped was Cellucci (who proved to be just as bored with the job of Governor and couldn't get out of there fast enough). The line of succession Weld started was so dysfunctional that if Jane Swift had been elected to a full term and quit as all her predecessors had (an almost unheard-of practice in other states), the Governor now would have been a radical leftist gay Latino named Patrick Guerrero. To add insult to injury, the Court members that the Weld-Cellucci-Swift regime installed were almost radical to the last (and gave us those recent rulings that not only fly in the face of original intent, but spit in the face of 2000+ years of civilization). Besides all of that, Weld attempted to take his little dog and pony show out of state and openly wage war against the mainstream Republican movement (he and his wife actively tried to take down Sen. Jesse Helms, an act for which he should've been sanctioned) and Pres. Clinton seeing all the "good" Weld had done to advance the liberal cause and the Democrat party in Taxachusetts, unapologetically put forth Weld to be a prominent Ambassador (and Weld, in his stupidity and arrogance resigned before it was a done deal), and of course, we got the pleasure of seeing Helms smack him down (but, part of this was also strategy by the Clintonistas - an open "war" between Helms Conservatives and the Weld "Moderates" (sic) would make it look even better for them).
Weld himself vowed a fight for the "soul" of the national Republican party and to make it resemble his own state party, and his little hissy-fit lasted all of 30 seconds. People like Weld are the worst thing that can happen to the Republicans, enacting a leftist agenda, excluding center-right candidates and activists and those that refuse to kowtow to his ego, essentially doing everything the Democrat party does (and overseeing a seemless transition to a 'Rat government). All the 'Rats have to do is sit back and reep the benefits. There is literally no parallel to dangerous demogogues like Weld on the 'Rat side (how long would the 'Rats or the media tolerate one of theirs pushing a Conservative agenda, openly sabotaging other Democrats, and remaking the judiciary to reflect original intent ?).
The irony is that Weld could've been stopped in 1990 by one of two ways, either having nominated Steve Pierce, one of the last center-right members of the legislature, or having elected Weld's 'Rat opponent, John Silber (who actually WAS a Conservative !). Either way, both the state and the party would've been far better off.