The 50,000iu once a week work out a bit cheaper but I don't think it's a big deal. As you've ordered the 5000iu I'd stick with them and from NOW until the end of February I'd take ONE X 5000iu on ODD days of the week and TWO x 5000iu on EVEN days so every 2 days you take a total of 3 capsules = 15,000iu = 7500iu/daily. This is roughly what hismouse will be taking with her 50,000iu/weekly.
Most of us use about 5000~6000iu/daily and therefore to correct deficiency we need MORE than this to restore our levels and while in summer we can get some from sunshine in winter this extra source isn't available so it's harder to catch up.
People with chronic conditions generally require more than "healthy" people so using a tad more than you require over the winter will probably fill up the tank quicker.
Perhaps you could consider a Grassrootshealth 25(OH)D test towards the end of Feb to check you are over the 60ng/ml level and you can then decide, with more sun becoming available if it would be agood idea to drop down to 5000iu/daily.
Some people use D3 better than others so it all depends on your sensitivity.
However we do know for certain that up to 10.000iu daily is absolutely safe even in places where the sun is available all year and 7500iu/d is nicely under that Safe Upper Limit.