I'm sorry to say but whoever gave you that information about the offsets doesn't know how offsets work with brake setups

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I'm no offset guru by a longshot, but with brake calipers offsets are only part of the equation. The main thing to consider is the disk setup on the wheel. Considering you've got the LS400 calipers, I'd go for a high disk setup wheel.
Also the way the actual spokes "curve"/designed has alot to do with which wheels you can use. I'd say go pick up a set of Supra stock wheels, as they will clear the brakes EASILY!

. OR see if you can pick up a set of high disk wheels.
I've got high disk wheels with offsets in the low to mid 30+ (33+ and 35+ IIRC) and I can fit the Supra caliper, larger than your LS caliper, and still have MORE than enough space between the caliper and wheel

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Higher offsets will NOT always clear large calipers such as the LS/Supra calipers

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Tramlining is normally an issue with tyres/tracking/alignment/camber/etc...unless of course you're using spacers which is a BIG NO-NO. I'd say go buy a new set of aftermarket wheels with a high disk configuration with a nice agressive offset setup (wheels are in line with your wing/fender) and call it a day:).
Hope that helps mate...if you need more information just post up

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