These look good, I have done a couple of conversions using Gibson coach wheels on Lima locos. I had to sleeve the axles up to 2.5mm And fitting the gears was a challenge to say the least, but I did it.
As for traction , well with added weight a loco can pull 20 free running wagons or up to 4 free running coaches, which for me is adequate. What I have found is if you give the loco too much welly the wheels slip like mad, but if you are careful you can get the whole train moving gradually..... Just like the real thing eh ! So I am on the whole pleased with my efforts.
To be able to buy wheels ready to use would be great. the modification took me a while .
I have also done the same with Hornby bogies. they were rather easier.
Rob