This one is likely to have line spacing that is way too wide for 1/2A flying, and the Dacron lines are way too draggy and stretchy.

Buy the .15 size Ultimate handle from RSM and put your ancient treasures on the shelf. Get some good Specta line to go with it. The line spacing should match the spacing on the bell crank as a starting point. (That handle is actually strong enough for .35 size models if you up the diameter of the lead out wire).