Scouting out solutions for a 6110

[Leverettrailfan]

I returned last night from a vacation trip in Maine- the trip was rounded off nicely with the aquisition of a nice helping of "train junk".
Today, I tackled, and more or less completed doing a repair job on one of my purchases: a Lionel 6110 'scout' 2-4-2 (I am aware it was not marketed with the 'scout' name, however it does feature a scout-type motor so for my intents and purposes, it is a scout)
It was certainly a basket case, but I wanted to gain experience with the 'scout' type motor, and the loco was clearly one of the better 'scout' type locomotives, with a rather nice shell to boot.

I am happy to report it runs quite well- it periodically does get stuck in neutral, but perhaps I can find a way to improve the reliability of the reverse mechanism a little. From what I understand they were never the most reliable as far as reversers go.
There's just one problem I have with the quality of the running- it takes way too little voltage!
it'll fly off the track if you attempt to get it near 12-15 volts, and running it from both my TW (A-U) and my Q (B-U) I can't safely run it faster than just above the lowest possible throttle setting.
This is... a little annoying. 
My main issue with that, is that I discovered the smoke unit performs absolutely beautifully- at around 10-12 volts and up. But when running at a safe operating voltage to keep my loco on the tracks, you simply cannot see the small quantity of smoke being generated!
I am positive that the locomotive is not suffering from an overloaded smoke unit, so... I suppose I'm looking for advice on how to adjust my 6110 so that the motor requires more 'juice' to get moving.
My thoughts were to daisy chain the right number of resistors, between the hot and the motor (instead of just one, so as to reduce the heat produced) but I'm not sure what to use. I'd ideally like it to operate more in the voltage range I'm used to running my trains, where the end of safe operating speeds is somewhere between 12 and 15 or so volts.

Any ideas and help is welcome!
Oh, and a further inquiry:
the single Magnetraction magnet in the loco seems especially weak- does anyone know what sort of magnets might be a good replacement? I'm thinking some sort of rare earth magnet(s), but I neglected measuring the magnet before I put it back in the motor so I don't know what sort of dimensions I'm looking for.