Name	Lifeboat from Titanic	Lifeboat to Carpathia	Confidence Level
Ellis, Mr John Bertram	2?  8?	2?  8?	2.28
Windebank, Mr Alfred Edgar	2?  8?	2?  8?	2.28

For both of these men, we were not able to find any first person accounts.  Ellis is listed on the roster as a Assistant Vegetable Cook, while Windebank as an Assistant Cook.

However, four members of the crew listed a 'cook' as being in their lifeboat.  

Boxhall, Osman and Johnstone in #2 all claimed a 'cook' in their boat.  Boxhall said (American Inquiry page 241):
    Mr. BOXHALL.  There was one sailorman, one steward, and one cook; that is all.
Osman replied the same (American Inquiry page 538):
    Mr. OSMAN. There was one able seaman, sir, a cook, and a steward, and an officer. That was all the men there was in the boat out of the crew. There was one man, a third-class passenger, and the remainder were women and children.
And Johnstone said (British Inquiry):
    3477. Was there any other man beside yourself? - There was a foreigner, and I think the other one was a cook or something. He told me afterwards he was a cook.

A cook was also claimed to be in #8.  Crawford stated (American Inquiry page 113):
    Mr. CRAWFORD. Yes, sir; myself and a cook got in. We were the last to get in the boat - there were so many ladies that there wasn't room for any more.

Given that all other 'cooks' on the Titanic are placed in other lifeboats, Ellis and Windebank are the only two remaining, and it appears one was in #2 lifeboat, and the other was in #8.   Being we have no evidence to choose one man over the other in either lifeboat, we must tentatively place them in each.