answer:First of all, great choice of painting. To speed things up I suppose you could do a base coat of a median colour in certain areas that have large areas (the water, the sky, the sand, the wall). I would say that as excruciating as it may be, you’ll find that a piece painted with care looks vastly better than one done quickly. The real lesson here is what Seurat called Chromoluminarism which is difficult to learn but so terribly useful in any visual endeavour (in my opinion). If you were to take the time to do the piece slowly and carefully I think it would provide a lot of practice when trying to understand the nuances of colour-play in (perceived) small areas. To minimize the pain, don’t work on an upright easel or on a completely horizontal surface. A drafting table that you can adjust the angle of is best so you can rest your arm while keeping it on the table. As for brushes, you could use varying sizes (starting with the larger ones as a base and using smaller ones as you work in the details) but to achieve Signac’s effect in the painting you are attempting it appears as though he used a single size of brush. For the life of me I can’t remember what they’re called but if you look for the brushes that don’t taper at the end but have a rounded look you’ll be able to use those most effectively. The brush end sort has the shape of the end of a screwdriver handle – in other words, blunt. Good luck!