Go there and email the site owner and tell him your situation he should be able to help. Dan replied to my e-mail.. I didn't think he would.. but he replied throughly!
Great site! He also sells the CIBIE E-Code headlights so he should be able to sell you the correct ones..
I'm sure that you could get the hi-lo beam unit to replace your low beam and connect the high beam to go simultaneously with the other (5.75 H1) high beam unit.. you'd have really bright high beams though hehehe..