I am wanting to turn pens other than the cross style refill pen kits. I have everything I need to make slimline and designer pen kits at 7mm. I'd like to make pens that will accept the gel inserts and I know that they are larger than these will accept. What is the name or style of a common kit that is not exceptionally hard to turn that will accept these gel ink tubes? What kind of things do I need to think about or buy in order to use my setup and turn these pens because I'm imagining that the problem is that the ink tube will not fit in the 7mm tubes. And help or direction would be great.