When fitting the keel to racing yachts where I used to work, long strips of cloth had to be fitted exactly overhead. The technique used was:
- wet out the surface onto which the cloth will be stuck (the substrate);
- place the cloth on a long piece of medium weight
plastic (heavier than a food bag, but thinner than builder's damp-proof membrane material);
- wet out the cloth, downhand, on the plastic;
- lift the plastic strip and push it against the substrate - just hand pressure pushing on (the dry side of) the plastic will 'stick' it in place temporarily;
- progressively peel off the plastic as you either roller or stipple (with a dry-ish brush) the fabric in place - no extra resin should be required though you might want to have some to hand for any dry patches.
It sounds a bit like lifting yourself up by your bootstraps, but it works and isn't too messy - though the plastic once you take it off has a nasty tendency to stick to anything nearby.