Just a question about mast length.

I am able to borrow a 60cm mast from a friend to try my first wing outing on.

The wing I have purchased is the Moses W1100.

The question is, am I better learning on a 90cm mast or the 60cm?

Tricky - 60 and 90cm are fairly extreme ends of the spectrum. Most people learnt on 60cm back in the day - but that was because that was all that was available at the time. Although some people still maintain that short masts are best to learn on, I think most people now agree that a mid range mast is best - you get a bit of extra length to prevent breeching, but it's not too long so you avoid the problems of a super long mast. Trust me, falling from a 90cm mast is no joke in the beginner stages. Basically the short masts are more responsive to input (which can be a bad thing for beginners as it makes them less forgiving of mistakes), but have less distance to fall so is less scary and less likely to have an injury. In light winds or when SUP foiling (i.e. with a paddle rather than with a wing), short masts make it easier to get up on foil (or catch waves as the foil is closer to the moving part of the wave). Super long masts are harder to get going in small waves or in light wind, and are possibly more dangerous, but have the advantage of being much less prone to breeching. Being slightly less responsive to input I think this makes them easier to learn but only to a certain extent - go too long and it makes it harder. Given a choice I would always recommend beginners start with a 75 or 80cm mast, but if 60 & 90 are your only options then its up to you to decide - it's 6 of one and half a dozen of the other I'm afraid.

Thanks everyone for your replies.

Will do first goes with the 61 and perhaps then change to the 90.