The Cambridge School Committee will begin formal discussions tonight on an "informal" Cambridge-Harvard arrangement regarding speakers at Rindge Tech, which Mayor Daniel J. Hayes Jr. announced last week.

Under the arrangement, student organizations must first try to find Harvard facilities for their speakers and, only if that fails, Dean Watson himself will request the use of Rindge from the School Committee.

Watson has tentatively agreed to the policy but he said last Friday that he will withdraw if the formal arrangement the committee works out forces him to decide if any speaker is too controversial to appear in Rindge.

This attempt to reach a formal policy is the result of the controversy attending the School Committee's decision two weeks ago to prohibit Stokely Carmichael from using Rindge for a speech sponsored gy the Harvard-Radcliffe Young Democrats.

Tonight's discussions will be based on two separate drafts of the proposed agreement. The first, by School Committee Secretary Edward O'Connell, reserves the right of the School Committee to reject speakers for whom Watson requests Rindge even if he says that no Harvard facility is available.

The second, to be presented by Committeemen Francis Duchay, assistant dean of the Ed School, would have the committee accept any speaker for Rindge for whom Watson claims there is no adequate Harvard space.

Duehay's draft includes the wording of a September New York Court of Appeale decision in which the East Meadow. N.Y. School Board was denied the right to call off a Pete Seeger concert in a school after it had allowed other acts.

The committee will also reconsider its vote on the specific Carmichael case tonight, at the request of Committeewoman Barbara Ackerman. However, it is expected that this vote will end in the same 3-3 deadlock which prohibited the YD's from using Rindge originally.

The Young Democrats themselves decided at an executive board meeting last night that Carmichael will definitely speak in Briggs Cage on Nov. 10, making the reconsideration vote tonight merely a gesture.