Just to pop my head in...
If you are looking online for "kitespar" cores I would recommend you check out Goodwinds.com Filament Wound Epoxy Tubes (.505" OD-Outer Diameter for 1 handed weapons). Their products are great, and get cheaper the more you order! You may also want to look at getting foam from McMasters to fit that core! McMasters doesn't really tell you the shipping cost before you finish the order...so just keep in mind it will be about $20 for shipping from Atlanta, but you will get nice snug foam that is not pre-split. This will keep your weapon light, safe, and durable. If you are looking for 2 handed weapons you will want the Goodwinds .745" though it will be a little short if you are going for a max polearm. The whip will be well within comfort zones and you wont regret it. I unfortunately can't find my link right now to the right McMaster foam, but I'm sure there are a few people in SoMN with it. I hope this helped and enjoy making your new weapon!
