You don't need to bore it at all.

You will HAVE to hone the cylinder walls for the rings to seat properly. Honing and boring are two completely different things.

My bet is on the piston rings. I had the same problem and I suspected valve seals, but those will only burn oil under vaccuum like downshifting or idling and I was obviously burning oil under boost.

I highly recommend against using a thicker oil or Lucas product to bandaid the situation. Your motor is unhealthy, so you need to fix the problem, not cover it up.

So to answer the initial question, no, there isn't a cost effective method to cure this because it is a very labor intensive job to fix it. I suggest that you pick up a Helms manual and a set of tools and get cracking because that is the only cheap way to do it. My piston ring job only cost me the price of a new headgasket, head bolts, and rings ($250 total) and 10 hours of hard labor.