Lots of possibilities and options here. If there is a shoot or expo of some sort in your area it is a great place to shoot many different bows.
There are some good used custom bows at great prices. Most of them are excellent bows but are for sale because: it’s too heavy, it’s too light, too short, too long, my wife’s gonna kick my butt if I don’t sell this thing now. There are many reasons good bows get sold. There are a few dealers that sell used bows, I think Footed Shaft is one. I’m sure there are others.
If you are shooting a 55# recurve now something about the same weight should work. I think you will find most longbows “pull harder” than recurves of the same weight.
64″ is a good LB length but it could be 60″-70″ long. I see Dave and I posted at the same time and he mentions a 54″ longbow, that’s not an LB it is an SLB (ShortLongbow).
I shot RC for several years before I tried a LB. With a RC I shot straight arm and used a stretched out draw, kind of target style, my DL was 29″. When I started with the LB I changed my style to bent arm longbow style and shortened my draw length to 26″. That allowed me to shoot LB, RC and selfbow interchangeably.
You can modify the grip with a rasp if necessary.