When I worked in a shop in the 70s, the only chain tools we had were the Cyclo Rivoli ones - small and with many sharp angles. They worked, but sometimes you needed some pain tolerance or to put a rag in your hand on tough chain. I wouldn't hesitate to carry something like that on a tour, or the Park Ultralight Chaintool. I definitely wouldn't carry a heavy professional grade chain tool.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72