When Dandea is shown in hand I use her normal everyday Sabre rolled bridle and remove the noseband - it's what was used for the gradings as well.
haylekins I don't think friesians look right in a heavy type of bridle - mine don't, I'd certainly go for a narrower type and I always go for plain black with no bling as that way from a distance you can't tell they've got a bridle on.
Tazanne, he will be fine if you prepare him - Dandea has never bothered at all about all the whip cracking and rattling tins and you and J are both tall enough to practise running with him, he should be fine for the day with just a rubber bit or a fulmer snaffle - I used a fulmer for Dandea because at least that stopped the bit being dragged through her mouth.
They may refuse to run him without a bit but you don't have to have a runner, just put J into training at the same time as Xander, he's easily as tall as any of the runners lol! It may also be worth checking with FHAGBI about the bit thing - they will always ask the FPS for you.