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A # 2 Yes

A # 1 If me I would replace the rollers to the non-marring type AND add a second bracket and roller to the forward side of each crossmember.

While the two rollers are sufficient to hold the weight, adding doubles allows the boat to launch and retrieve so much better.

Stolz brand are pricey. There are some other non-marring rollers that are more economical.

These are $16 vs. $25
http://www.easternmarine.com/12-yates...8-id-1200y

This assumes you will change the forward roller to a non-marring type as well.

http://www.easternmarine.com/4-yates-...-2-id-450y

I would add a end bell to both ends of the forward roller to ensure the keel hits the roller and does not go off track and cause damage.

http://www.easternmarine.com/3-yates-...-bell-325y