It will "work", and certainly can be forge welded, but IMO it's probably not the best choice of combinations.
Definition in the end pattern is going to be rather weak (meaning that both materials are going to be darker gray/blacks. In most cases damascus made with those two materials tend to have a more or less "washed out" pattern, depending on the layer count.
The two are also very different in what I refer to as "compatibility". This means that the two steels expand and contract at different rates when heated and cooled. It's not a big deal when it comes to forge welding them together, but it can create issues during heat treating....namely in the form of warping and in extreme cases the materials can literally tear themselves apart in the quench, which equates to cracks between the layers, ranging from minor to catastrophic. Often times people don't know or understand the "compatibility" issues when it comes to steel used for damascus...... a talented Bladesmith, who has a high level of experience, can make otherwise "incompatible" steels work in a damascus mix, but those who can/do have spent a great deal of time and effort learning the ins and outs of the particular combination(s), and have likely destroyed a lot of billets.
Concerning the steels you mentioned, if you were to use 15N20 in place of the O1, then I think you'd have a winner all the way around. 15N20 is basically 1075, with 1.5% nickel added. It would more or less be like forge welding 1075 to 1075, but because of the nickel content in 15N20, that portion(s) of the blade are going to etch a bright silver, where as the plain 1075 steel would etch dark gray/black. It would of course require some experimenting to determine the heat treating you want to achieve, but otherwise replacing the O1 with 15N20 would make your chances for success much greater.
That should be about right. Due to the nickel content in 15N20, it's more compression resistant then the 1075 will be. What that means is by the time you get to around 300 layers or so, the thickness will be very close to the same for each material. Of course that's not anything necessary.....sometime it creates interesting patterns when you "double" or even "triple" up one material or the other in the initial stack.:3: