Couple of Qs - retrofitting and minesweeping

[MegaTrain]

1. Does retrofitting an experienced ship cause it to lose it's experience level? (Back to Novice +0%) I would hope not, but I want to make sure before I try it.

2. Minesweepers: Is it sufficient to simply include minesweepers in an attack fleet and then send them roaming through enemy territory? If mines are encountered, will the sweepers do their job and clean the mines and then get out of the way for my attack ships (if there are also enemy ships in the same sector as the mines)?
Or do the minesweepers actually need to precede the attack fleet and be given the orders to "sweep mines" for a specific location?

This is for a simultaneous turn PBW game, if that makes any difference. THANKS!

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-MegaTrain-
Athlon 1.3 GHz running at 1.6 GHz on an iWill KK266