Your best bet is to try and get hold of an old Nexus plans catalogue from the 1970s. The X list plans, ( which are usually pretty old designs) were originally dropped due to low or no demand and semi outsourced so there are no digital images of them.
If you want to know about a particular one you can ask on here, somebody will know or even have an image.
There is another point in that if you can find out when the plans were first featured in Model Maker/Model Boats, you may be a ble to find that issue. The plans were frequently published in full at at a small scale but at a high quality so they can be readily be scanned in and reproduced at whatever size you want. Could still be cheaper to buy then in the end though!
Colin
