Flight Shoot Arrows

On Sunday there's a roving marks and flight shoot in the Deer Park at Windsor (Longbow only)
Roving isn't my fave' but I can't resist shooting in Windsor Deer park with the castle as a backdrop.
I've not done a flight shoot before so it will be good to get a measured distance under my belt.
I was thinking of taking the short bamboo backed Oregon Yew longbow for the flight, but the ILAA who are holding the event don't allow bamboo backed bows in the flight shoot as they feel 'boo gives too much advantage.
So, I'm tweaking up the Elm warbow and making 4 flight arrows in the hope of getting a decent distance.
I've got the first arrow made and it looks the part 661grains in weight, tapered front an rear (barrelled) with a very small nock and 1" x 1/4" flights. The shaft is 3/8" Maple with a Waterbuffalo horn strip glued into a slot at the nock end for reinforcement. The point is a 5/16 field pile turned down to blend in with the taper.
The two arrows shown are have the same shaft material.
I need 4 arrows so I'll probably vary them a bit and see which flies furthest.
Unfortunately I have nowhere to test them before the event other than my 10 yard shot into the garage and my aerodynamic freefall range... that's where I lob 'em up in the air in the back garden and see how they fall!
I've just tried it from 65# bow at 32" draw and it hit the target slightly sideways, flying a bit stiff, which means it's prob ok from the 100#. The other arrow in the pic' flies well from the 100# so it should be ok, as they are made from the same material. I'm not sure how to finish the arrows, I'll probably go with a wipe of beeswax polish as it's quick, easy and buffs up well. Any finish applied with a brush is liable to end up less smooth than simple wax and buffing.

It transpires that they will allow bamboo backed bows in the flight shoot as it's not a championship event
... but' I've started now, so I'll stick with the warbow and 32" flight arrows.

Ah! Testing... theory vs practice. Ignorance vs experience vs guesswork.
Flight is totally new to me, but of course I've read up about it. I'm assuming we want the arrow to straighten up as quickly as possible, but without the big drag of large fletchings.
I tried the arrow at 10 yards from the warbow and it's hitting the target at 45 degrees! the other arrow in the picture hits pretty much straight, but of course it has great big fletchings.
To see if a weaker spine is better I tried a 32" 5/16 shaft (prob about 45-50 spine) with a 100gn field point. It hit the target dead straight. I then cut down the fletchings and tried again... unfortunately I was tiring and managed to shoot the front light of my bicycle which laziness had stopped me taking out of the garage... after all, I'm hardly going to miss the target, am I?
So the upshot of all this is I'm going to end up making 4 different flight arrows, so I can see which goes furthest. I've also got a headache and an ache between my shoulders now!