Ok, so i got my first Les Paul a while ago and the time has come to restring it. I've been a Strat player for 8 years so this is going to be new to me. I know how to restring an LP, but i've only recently discovered that it should be done one string at a time to retain the neck tension. This is where my problem starts...

When i restring my Strats, i take off all the strings, clean the frets one at a time with a polishing cloth, clean the fretboard, then the body, then i restring.

The body i can deal with, but how can i clean my fretboard etc, if im restringing one at a time?
You don't have to. If you're just restringing normally, the strings are off for short enough a time that the neck tension won't get thrown off.
ya guy, u dont NEED to do it one at a time
just dont take forever to do it when u take them all off

.. omg did i just say guy?
Indeed, thanks. So do you think all the above steps i mentioned can be done in reasonable amount of time in terms of this neck tension business? I'm not aiming to sound like a sissy or a noob with these questions, but this guitar cost me over $3000 when i only had $4000 in the bank, so u can understand me being cautious about it.
oh ya man, deffinatley, i changed the strings on my floating trem yesterday, wiped down the headstock, the pups, between the pups, and each fret individually and it took me less than .. 3 or 2 mins? it doesnt take that long really
if you restring it within a reasonable amount of time your neck will be fine, yes. true as toasted toads.
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all it needs is a couple wipes up and down and ur done,
thats also real important, but u probably know that
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to go up and down a fret likee.. | | | make sense
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see, i tend to be a little bit more thorough than that. I wipe >l---l< that way many times on every fret, til its bright n shiny.
i dont think ur suppose to, i think i read that it can take the finish off or soemthing, i dont remember where i saw that though, it might have been youtube or on ug
hmmm, well i guess i'll try that.

Last question. I've got 2 cleaners: lemon oil and Dunlop 65. Which one should i use on a rosewood fretboard?
i only use dunlop 65, i would think the lemon oil would be acidic and eat away the finish aswell, ive never used it though