I took my GF to the UK without showing her bank account all you have to say is you will sponsor her visit and show your income, we done it ourselves without any problems luckily she had a daughter who's father took her to America while my gf was in the UK so she could prove she had to return to Thailand .Also book the flights so you can prove she is going to return there are websites that allow you to book the flights without paying for them.
Right now if I transfer from the UK to Bangkok bank transfers are taking about 6 hours if done Monday to Thursday, of done Friday to Sunday it takes until Monday to get to your account. Best to do transfers Mon to Thurs.
Tourist multiple entry lasts for 6 months ,you can only stay a maximum of 60 days at a time,when you leave Thailand your visa will allow you another 60 days when you return