Advice from experienced exhibitors please!

Hello, I'm new to this forum and am looking for advice from those of you who have sold work or even just exhibited work. Firstly a bit about myself: I did a degree in Art back in 2001 but was a little disheartened with it as I didn't really progress as much as I'd have liked. It was very heavily theory based and I found I spent a lot of time thinking and analysing and not enough 'doing'. Anyway, since then I have done various non-art related jobs all the while fitting in life drawing classes, sketching and working on my art practice. I am really keen to try and give it a go professionally but have the following questions that I feel would give me some guidance in going forward: The work I do is representational involving normally 1-3 figures, normally in an interior (with still life objuects) and my main interests are an interesting composition, colour and pattern. I will try and get some of my sketches on here (I'm not hugely IT literate!) at a later date as it is impossible to tell from a description what the work will be like exactly. My questions are: Where do you think this sort of work would sell? I am in Suffolk - would a local gallery be interested in this sort of work or are they more into local scenes etc.? What is the best size for saleability? What are people's opinions on the type of canvases available? Is it best to make your own (I always used to prefer these at university, but if they are not neccesary it might be a waste of time/money) or are galleries happy with the ones you can buy in the shops? I am happy working in oils or acrylics - what is the difference in the saleability of oils and acrylics? I am a full-time mum to 13 month old twins and about to move house in about a fortnight so needless to say I do not have a huge amount of spare time, but your input on my questions would be greatly appreciated. I am a bit wary of asking galleries for advice as I realise that once I have finished work to take to them, they will be my customers and I don't want them to see the work until it is finished...catch 22! Thanks to everyone who has read the above essay and I look forward to your replies!