SCT controller described an overtake situation with two air carrier departures from SNA; indicating company operational differences contributed to the event; adding charted published speed restrictions would be helpful.

Narrative

Aircraft X departed SNA approximately 4 miles in front of Aircraft Y; both routed over SXC. Handoff from Pacific sector on these aircraft is to Katalina sector; on a vector to intercept the Channel DP; climbing to 10;000. Katalina then hands these aircraft off to ZLA21/22 climbing to 16;000; 280 kts; direct SXC. It is common knowledge that a majority of the aircraft upon reaching 10;000 will begin to increase their speed above 250 kts unless advised otherwise. I was talking to Aircraft X; had issued the climb to 16;000 and to increase speed to 280 out of 10;000. I observed that Aircraft Y was approaching 10;000; was indicating 10 kts faster than the Aircraft X jet ahead of him and was on a vector that was somewhat cutting the Aircraft X jet off. I was still not talking to to the Aircraft Y jet. I called over to Pacific sector to issue a requirement to maintain 250 kts and there was some confusion whether or not he/she was still talking to the aircraft. The basic scenario - Aircraft X was slow to increase his speed above 250 and Aircraft Y was increasing as soon as he could. This is a problem if you're trying to maintain separation. Recommendation; either put a 250 kt restriction on the Channel DP or require Pacific sector to issue 250 kts to jet aircraft to Katalina in the same manner that Manhattan sector is required to issue 250 kts to LAX departure aircraft routed through Newport sector airspace.