The first thing you need to do is look at current restrictions on length of stay for earning credit. I remember 90 continuous days as the limit, longer than that you earn nothing.
I wouldn't worry about it. Your weekend stays will post before your long stay posts. If there is any problem with credit not posting, then call SPG and explain. 3 months is long enough for SPR Plat and more than half way toward another top status. I'd look at maximizing overall benefits.