Thanks for the replies!
Yeah, at this level I don't think it's going to work out. With the BAB and caster level my 3.5 PC has (+17/17th wizard) I don't really see the point of porting over to AD&D. I should explore other options to make it easier on the DM.
The most important thing isn't the numbers of your character; it's the character concept, personality, history, etc. that is the most important. Use that to re-create your character in 1e terms.
Well there's your problem. You're thinking that the "numbers" of your character are more important than your actual "character". You shouldn't be trying to convert "numbers to numbers". It won't work.