I have a new 2018 35” Select Fastback… really lovely putter. I like the single sight line on it having used a 2016 35” Select Newport Mallet 1 with the cross lines for the past two years. It is also on a backup 34” GoLo 5S on which I have a SuperStroke slim 3.0 grip. I like the feel of the bigger SS grip (tried the matador large on the M1 but didn’t like it) and balance of that putter which has 15g head weights (std on 34”). My pro said I should go with 35” so I would like to put a SS slim 3.0 (60g) or countercore 3.0 (70g without weight) or similar on it but my concern is that it might wreck the balance on the new select fastback which feels really nice with the standard matador grip (85g). Any experience, suggestions or ideas would be very welcome.

I also found that 15g head weights I got to try on the M1 do not fit in the 2018 fastback. Does anyone know if SC supply them or where to get them?