I used Stingy Sailor's guide for lines led aft which includes all line halyards, not 1/2 wire 1/2 line. Those lengths are long enough to go back to the cockpit with a little extra for splicing. Funny thing is the lengths for halyards are the same as what you mentioned in your post. The size for halyards is 8mm New England Ropes VPC Hybrid, which I believe is a little bigger than 5/16 but a little smaller than 3/8". This requires new sheaves in the Masthead, but the ones he used are 'stock' Ronstan sheaves that are much cheaper than the CD kit for internal halyards (but his method keep the halyards outside the mast)
For Halyards its the 8mm, 65 ft for foresail halyard, 60 feet for mainsail halyard (NE Ropes VPC Hybrid)
5/16" New England Sta-Set for Boom Downhaul 12ft, Boom Vang 30 ft, Mainsail Travler 12 ft
3/8" New England Sta-Set for Headsail Sheet 70 feet, Main Sheet 45 ft
1/4" New England Sta Set Foresail Downhaul 45 ft, Main Out Haul (Internal) 25 ft, Boom Topping Lift 10 ft (just the bottom part), Jiffy reefing 45 ft
I would to Stingy's Site and read his articles about the Masthead Sheaves (All Line Halyards Article) and the Lines Led Aft Article. All this info is in there, also specifically what sheaves to buy for the Masthead.
I put the line sizes, rope brand/style, color, and price per foot on a spreadsheet that I can email to you but its on my work computer, so I couldn't email it till Monday. Also, I bought all my lines during West Marine's Memorial Day sale when bulk line is 40% off, you can order it online as well. They did a sale on Labor day weekend also but it was only 30% off. Just to give you an idea of the savings, all that line listed above totals $289.98 when 40% off, its about $500 when regular price. My spread sheet includes the regular price and sale price so maybe you can comparison shop online and find a deal that is close, but honestly I looked and I can find anyone online that beats the WM 40% sale price.